TW; body image issues, ED

I am aware that I am technically not overweight by any means, this is definitely more about body image than physical health, but I wasn't sure how else to tag it.

​As a teen, I struggled with an eating disorder that kept me at 50 kg (110 lbs) until I turned 18. Eventually, I began to heal my relationship with food, and by the time I was 20, I weighed around 52 kg (115 lbs). Since that wasn't underweight for my height (152 cm / 5'0"), it didn't really bother me.

​Now, I’m about to turn 22. Admittedly, I haven’t been paying close attention to my weight or my food intake lately, certainly nothing like when I was a teenager, skipping meals and exercising like my life depended on it. I honestly thought I had escaped that dark place where my weight was the only thing that mattered.

As for right now, I am weighing 55kg (121lbs) and hadn't thought much about it until someone, in a very cheerful voice, said behind my back: 'Oh, she's gained a bit of weight!'

​And just like that, I started spiraling. Because they were right, I did.

​At first, I was in denial. I felt fine, and although one pair of pants was fitting a bit tight, everything else felt the same. But then I started obsessing, staring at myself trying to figure out why they said it, what made them say it... and then I finally noticed. My sides are a bit fuller. Just a bit. Enough for me to miss it at first.

​I panicked and started asking my friends if they thought I had gained weight. Maybe I was imagining things? I used to think I was way bigger than I actually was as a teen, maybe this was like that. But they all agreed that I had, in fact, put on a bit of weight. Always adding that it wasn't that noticeable, and they didn't think it looked bad at all. Because, hey! More ass!!! Right??

​The thing is, even though they’re being nice about it, I can't help but feel like they're just trying to spare my feelings. I’m terrified that this weight gain will somehow spiral out of control and take over my life. I'm scared to eat again, and I’ve fallen into this exhausting cycle of restricting food only to binge later when the anxiety gets too heavy.

This is not the first time someone mentions that I've put some weight, but I always managed to ignore it. But now ​I feel this intense pressure to go back to the gym, even though I don't have the time and I honestly hate it because it reminds me of my worst years.

To make matters worse, I've started having these weird dreams about food, like stumbling across a giant burger and eating the whole thing, just to feel sick when I finished it.

I just... idk what to do. I need some advice or reassurance. How do I feel better about this?