I put on weight, partly due to medication, partly due to eating comfort (junk really) food, and partly because I just didn't care at the time. I've got it off and am trim now, so it's certainly possible -- even for an unathletic slug like me.

The confidence is a tough one. I'll get back to you on that -- someday.

As for the little starter improvements ... rather than trying to recreate and put together a list of advice now -- let me do a little dredge on my prior posts....

(some of these cover social anxiety issues as well, so filter that out if that doesn't help)

https://forums.psychcentral.com/5799517-post3.html

https://forums.psychcentral.com/5861069-post3.html

https://forums.psychcentral.com/5886202-post2.html

There's advice from other posters in those threads too, of course.
Hopefully some more creative people will chime in here.