Not eating enough calories

So I just started a new weight loss program (noom) and so far I’m really loving it. A little background about me is that I never controlled myself with eating. I ate as much as I wanted and as bad as I wanted. Well now I’ve gotten really into meal prepping and haven’t really had too much of a problem with self control except for the first day of my period when I ate everything in sight lol. Well since I’ve been actually eating nutrient dense foods I’ve been having a hard time eating enough calories because I feel so full. I used to eat so much but it was all junk food so I had to eat more often to stay satisfied and now I just cant seem to eat enough even when I try. And with my calorie counter it gives me more calories back when I work some off. I just feel like I’m under eating and I want to know if anyone has any tips. I feel like I’m forcing myself to eat all day long just to make sure I’m not under eating. Is this ok?