I have been making cakes for many years now. Never have I had A) a cake droop in the middle and/or B) stick to the sides of the pan and/or C) crumble when I took them out of the pan. All of those things happened to me the other day! I was so upset, that I burst in to tears. Suddenly I was a worthless, talentless loser. (thank you pregnancy hormones for making me a crazy woman LOL).

Anyhow, I talked to my mother in law, who is not an avid baker, and she seems to think that it may have something to do with the altitude change, as we recently moved. I believe the altitude here is around 3100-3200 ft.

Any suggestions as to what caused this? And what I can do to prevent it in the future? Thanks

Yep, high altitude baking is a new skill. Fortunately for me, I never was forced to learn it . . . However, Google it.

Are your cakes from scratch? The altitude could well be a factor.
Using mixes I baked (at different times) at sea lever, 3,000+ and even at 8500 ft and had little problems.
At the highest I had to increase the liquid almost double.
then there is the occasional mix that just is no good!! YES, that does happen.