Pregnancy weight gain

I honestly hate seeing the posts about weight gain/lose during pregnancy because everyone is different and every pregnancy is different and sometimes people can get caught up in a number that they think they should be at just because everyone else is gaining a certain way. Anyway, putting that aside.... I have a genuine question/concern regarding my weight. I’m currently 28 weeks 3 days and decided to weight myself before my appointment tomorrow (I don’t like surprises lol and don’t want to be shocked my the number in front of the nurses when I step on the scale tomorrow). I started my pregnancy at 159lb which is considered healthy for my height and athletic build. I’ve been gaining slowly over the weeks and was up 10 (170lbs) pounds 3 weeks ago at my last appointment. Recently I have noticed an increase in my appetite and have been eating all sorts of things so I was scared shitless to step on the scale today. When I did, it said I lost 1.5lbs?! I am super confused and a little concerned. My belly has definitely gotten bigger and I feel heavier (I honestly thought I was going to be closer to 180 but was only 168.3lbs). My question is, is this normal? I’m going to bring it up with my doctor tomorrow but was wondering if anyone else experienced this? I also do workout 5-6 days a week but I still feel like I should be gaining because baby should be getting bigger, right?!