Frightening memories/thoughts about weight change

Squalimous

When I was in my teens I was mildly underweight (1.60m & 40ish KG) I would say I was strong for my height/weight, but didn't have much stamina.

Then when I was in my late teens I fell very ill. I was bed-ridden for over two months and unable to eat anything and most liquids beyond water would come back up. I ended up weighing 29KG.
A few months after I got better I weighed 45kg (still a little underweight).

Then I moved out and ate poorly and stopped exercising for a few years. I slowly increased to roughly my current weight (68ish KG, overweight). Three years ago I started doing more exercise, but I only recently started paying attention to calories and increasing my exercise intensity.

Even though I definitely could lose some weight, I still sometimes have nightmares (and daymares) of the time I spend bed-ridden and severely underweight. Sometimes during the day I reflexively grab my arms to check the meat&muscle is still on them.

I find it hard to convince myself that my exercise & improved eating habits are for shaping and strengthening, and that I won't turn into a stick figure made of bone and skin again. I know it is in my mind, but I can't stop the fright.

Did anyone else experience something similar or know a way of dealing with these kinds of irration fears & thoughts?