
I started as literal skin and bones and struggled with this a lot!!! Basically, you probably have a SUPER active metabolism like me. If you think you're eating enough, you aren't. I found that, after tracking a lot, with exercise, I straight up lose my period if I eat under 2500 cals/day. I have to kinda force-feed myself sometimes.
Do not let yourself deterred. Keep lifting AS HEAVY AS YOU CAN. Get that good cardio in. Eat A LOT, and eat A LOT of protein. A LOT. With our metabolism, recommended intake isn't enough. You need MINIMUM 1-1 protein:body weight or more. The progress will roll in. I started packing on actual body volume around 1.5 years of consistency and diligence (I got results before that, but I was still just so fucking skinny. I'm talking actual hips, thighs, ass, dense shoulders, juicy biceps, 8-pack, etc)