Zombie mom needs help!

Hi lovely ladies! Not sure if anyone can help me but I'm getting desperate here.
My son just turned 3 months, he's 13 weeks old and had JUST started sleeping through the night when suddenly 4 nights ago he started waking up every hour to half hour from about 3-4am onwards. He's done it 4 nights in a row now and I still cant quite figure out what might be causing it. He isn't really needing a diaper change or hungry because he will just suck on the bottle a moment or two then not want it. He's started teething but doesn't seem to be acting like he does when his gums are bothering him. Sometimes I just pop his pacifier back in, rock him for a moment and he'll go back to sleep.
I would assume it's because I just had to change his formula from Kirklands (which he loved) to Gerber gentle because that's what WIC pays for, but he doesn't seem extra hungry and it's not gas pain.
So I can only come up with that it's just a developmental phase he's going through and that he'll grow out of it soon and go back to his normal sleeping pattern. But, this mommy is exhausted so if anyone has any ideas I would appreciate it!

    It could be the formula, but I don't really know about that.

    What I do know is that babies have a sleep cycle just like adults do. It consists of different levels of light to deep sleep that rotate. For babies the rotation is very short, like 30min to an hour. When adults hit the light sleep phase we may roll over, adjust our blankets, check the clock, etc. and fall back asleep. Babies don't know how to do that so when they hit the light sleep phase they don't have any tools to fall back to sleep. They wake up alone in a dark room and they're still tired so cry for mama to help. Since they're cycle repeats so often this could happen every hour. This is especially common between 3-4 mo because they've hit a new level of awareness.

    Tips to help are:
    Put them to bed drowsy but still awake - even if they fuss a little. It's scary if they fall asleep in your arms but wake up all alone. This also helps them learn how they can fall asleep on there own.

    If they wake up in the middle of the night try to interfere as little as possible. Comfort without picking them up by giving a pacifier or touching them softly. Keep the room dark.

    If they are hungry or wet feed/change them with as little stimulation as possible so they know it isn't play time.

    Set a time limit for crying and stick to it. Say once you put them down you let them cry for 3min before you go back in. Comfort then wait 5min, comfort again and then wait 7min. Of course make sure they aren't hungy, wet, sick, or need a burp. No need to torture the poor baby!

    This all will help the baby learn to soothe themselves when they hit their light sleep cycle. It may take a few days, but the better you stick to your plan the faster he'll learn. It will be better for both of you in the long run.

    I hope this helps! Good luck!
    Taylor thank you so much for your detailed reply. I think you are right. I think that he's having trouble drifting back into deep sleep and since I keep picking him up thinking he's hungry or something I'm probably making it harder for him!
    I am going to try your advice and try to limit my picking him up. It will be hard at first because I hate hearing him cry but I know the few times I just popped his pacifier in or put on his mobile so he could listen to the music he drifted right back to sleep quickly. I just never put two and two together.
    I will report back in a few days to let you know if I have any progress!
    Yes I usually give him a bath about an hour or two before bed time so he can start to wind down, then he gets to lay in his bouncer and get that last bit of energy used up and usually I will pop his pacifier in about 9 or so, or just put him straight into his crib at 9 with the mobile going and either way he will drift off. Then he will usually sleep until about 1 or 2am before he wants to be fed. He was just starting to get up to around 4 or 5am before he would wake before this business started.
    babies go through growth spurts and they wake up all the time during their sleep cycles. he really could just be hungry. do you try dimming the lights at night when its time to wind down? he just wants his mommy is all. waking up once or twice a night is normal. you just need to go to bed when he does! in another month you'll be adding a bit of cereal to his diet and that will hopefully help him sleep all night.
      Hazel I keep the lights dim and off once he's in bed. He's not just waking up once or twice though he's waking up every half hour from about 3am - 6:30am when I get up. that's more than normal for him he usually wakes twice at the most.
      It's not because he's hungry because I try giving him a bottle and he's not interested. I think that its what Taylor has said above that he's having trouble getting back into deep sleep now that he's more developed. I already give him a night bottle that has a few teaspoons of cereal in it to help him sleep but I had been doing that before this started happening so I already know it's not making and difference to the situation. Oh well I know it's just a phase and he will grow out of it eventually. But I just want to know what I can do to help him through it and I think Taylor has the right idea.
      About Lis Outland
      Current: Selma, North Carolina
      Birth: December 31
      On Moms.com since: Jan 11, 2014
      I'm the Mummy of a very beautiful little boy named Jayson. He and his daddy are my world. I'm an Aussie gal living in the USA.