Yep - I gained back over 100 pounds. I lost 75 originally a few years ago, then naively thought that since I lost it I could go back to eating unhealthy and be fine. I'm now pregnant, so not trying to lose weight, but it has been the proper motivation to eat better.
Allow yourself to be disappointed, but all the shame does at this point is further you into depression. Own the weight, and take control. One day making good choices in food and exercise is better than another day of falling into temptation. And if you do, roll it off your back - we all make mistakes and sometimes around the holidays, a cookie is okay. Just know that one cookie/whatever your vice is, does not make for an entire failed day.
You can do this! You've done it before, and you've got support so stop shaming yourself, so many people have walked that road. I might take up swimming since its easier on the joints and your body overall, are there any activities like that you may be interested in? I know changing up routine (especially if your job is taxing) can be a great thing.