Insecure and don't want to gain any more weight

I'm 15, 154cm and about 40kg at the moment, I have recently gained 7kg because after some very severe cutting and unhealthy dieting I was at a critical weight of 33kg which I originally dropped down to from 45ish kg. This messed up my hormones and my body, probably, even if I still feel "fine" after gaining back 7 kg, with a doctor's advice, I'm starting to feel insecure again, I'm terrified of being the chubby kid I was again and am feeling the urge to lose a kilo, and be like 37-38kg but I'm sure that's not healthy, and after a big party over a couple days where I ate a lot, I feel the urge to go back on a diet , so should I? I've been eating 2500 calories a day and it's been a lot, and naturally I've gained weight but now I'm terrified of getting fat. I also gained a lot of muscle from weight training, so my bodyfat percentage is still relatively low, but I'm still feeling really insecure:( I want to stop gaining weight