Welcome back! I'm recently "starting over" even though I only regained about 10lbs from maintenance. It's not so much the number on the scale, it's just the whole mental/emotional process of getting back on the wagon. I have found that getting started over is harder than starting the first time.
One thing I've found very helpful in these first few days of my start over is silly tiny goals each day that are almost a no-brainer to accomplish. It gives me that boost of "Yes, I met all my goals today, today was a win!" I was having trouble getting right back on plan. It's been my goal to lose these silly 5-10lbs for about three months. Big goals just weren't working for me. But these itty bitty goals are giving me my confidence and momentum back.
A few of my goals are things like "make 10 posts on 3FC today" and "write for 10 minutes in a journal about my weight loss thoughts" and "stay away from the cookie tin in the break room for at least one whole afternoon this week." Things like that
It's been very helpful.