How do i best gain some weight?

Judging from your other post, you really don't need to gain any weight. You have a beautiful body, and as long as your doctor says it's healthy-you should be happy with it. But if you really wanted to do something, gaining some muscle would be the healthiest way to gain weight.

But really, people on HeyCrowd aren't gonna know. Only your doctor, so ask him/her.

@Sarah(FAM/PMS) thank you!!