( Weight) TW: I randomly got my period back. Does anyone know why? I’m kind of like freaking out.

So I am currently 81 pounds. I haven’t had my period in two years now, I was inpatient and they got me up to 120 but as I expected I lost it once I left the hospital and I’ve been maintaining at like 80ish pounds now for about a year. I haven’t gained any weight so why did my period randomly just come back out of nowhere? I’m so confused and feel like it means I’m recovered but then again like I didn’t gain anything and now I’m gaslighting myself into thinking my scale is lying to me but I know it’s not since I put a ten pound weight on it and it weighed it accurately so I’m just so confused 😞