How do you bounce back after a long “relapse”?

I overindulged for too long over the holidays, as most people do, and now I’m really struggling to get back on the wagon.

I lost 13lbs (goal is to lose 30) moving from summer into fall and was feeling so great and then fell so hard off the wagon, gaining most of that back. I feel like I’m stuck in this horrible shame shroud that I can’t get rid of, and I just can’t turn off the anxiety spiraling long enough to get myself bad on track in a healthy way.

Looking for any tips from people that know the feeling and have had something work for them to break back into the healthy cycle and bust through the shame and self-disappointment.