I was about 295 when I'd started. Lowest I'd dropped to in about 9 months was 249 (around Thanksgiving), then came the holidays and since then until just now, I'd been in long stall at 256. I don't suspect I had a "damaged" metabolism, per se. It's not about fixing a damaged metabolism - it's more of a combination of a psychological break and the up-regulation of hormones that slowly stop functioning optimally after extended periods of caloric deficit. You could check out Lyle McDonald's investigation into what he calls the "full diet break." He actually recommends taking 7-14 days off where you eat at maintenance or some days slightly above, and a slightly increased carb intake (like 100-150g), every 4-8 weeks if you're sub-15% body fat, 8-12 weeks if you're 15-25% body fat, and every 12-16 weeks if you're 25%+ body fat. I'd never come across this theory before so figured I'd give it a shot.
I'll say this - something was up, and I'm guessing a big part of the problem was caloric intake vs. caloric expenditure, but I'm not sure if it was the whole reason for the stall, as I've been tracking (weighing) food for many months now. And I'd recalculated TDEE etc. etc. etc. I was tired constantly (even with 8 hours or more of sleep), irritable, foggy in the head - all apparently signs of a slightly down-regulated metabolism. And after 10 days of eating at maintenance (probably 2-3 days in there of a few hundred calories over maintenance), I felt like a new person. And, more importantly, I now feel great having dropped back into a significant deficit again. And like I said only about 7lb "gain" in water weight over that time period.
The stall isn't the problem anymore, the scale is moving again, I just want to make sure I don't have too significant a deficit to maintain muscle. I did, however, decide that despite what all the calculators I'd used were indicating in terms of my TDEE, they were too high, so I'm going with an even larger deficit. This very well may have been the main problem all along, like I noted above, but I'm in a much better place mentally about the whole continued process of dropping fat after that brief hiatus.
As I've gone through the process and written this out a few times in various forums, I'm realizing that what may have happened is (as a result of a significant period of limited to no exercise toward the end of last year) is while the scale went down, I'd actually lost muscle mass and so my TDEE was lower than I'd calculated etc. etc. It's just weird that I was fitting into smaller and smaller clothes but not seeing the scale move - right before I decided to take a brief break, I actually fit into 40 inch jeans for the first time since early high school.
In any event, I think I've got it all under control now. Basic gist is I aim for around 1,600 cals on non-lift days, and about 1,900 cals on lift days, which is roughly 35% deficit from TDEE.