Is all of the muscle I had when I was heavier and stronger still there?

I have been "dieting" for 6 months and have seen very good fat lose results. At the same time though, I was not as careful as I should have been and I lost strength during the process. My bench press was 250 and last time I maxed a little over a month ago I was at 225. I would guess I'm a little bit less than that now too based off of what I've been doing for sets and reps on bench. My chest is also noticable smaller which I am slowly getting used to (in all honesty I realize some of it was fat but it also feels and looks like the muscles are smaller). I have read that the only way to naturally lose muscle is through atrophy. Does that mean that all of the muscle I had when I was heavier and stronger is still there? When I go back to eating enough/slightly more than enough calories to meet my Total Daily Energy Expenditure will the size and strenght come back fairly quickly?