Already gained 15 lbs and I'm 22 weeks. According to weight trackers for pregnancy, I should've only…

Already gained 15 lbs and I'm 22 weeks. According to weight trackers for pregnancy, I should've only gained about 8?! My maternity clothes still fit the same (I bought them early) and only things that don't fit "properly" are my regular clothes (around the belly - of course, and my bras). I do know that I have put on a little body fat although hardly noticeable. I'm so confused!! I'm "allowed" to gain 10 more lbs.