Unless your doctor is concerned I wouldn't worry
When I was pregnant with my first child, I didnt gain any weight at all until I was 24 or 25 weeks, and only ended up gaining about 11lbs total. She was perfectly healthy. I am now pregnant with my son and am 26 and have gained 12lbs, more than i did my whole pregnancy with my daughter. Of course Im also 11 years older than I was when I had her. lol
I totally agree with you Janelle, keeping our appointments give our doctors a good ruler of where we're at and if we're where we should be.