We moved into our 45 yr old house about 3 years ago. When we moved in, I noticed that our kitchen floor sagged a little bit. No big deal right, it's an old house. Then i noticed that the bathroom door right off of the kitchen was sticking in the corner, on the non-hinge side. I sanded it down, to eliminate the sticking. Well, now it's back. I also notice that our steps going up stairs have started popping more than usual, and big pops in the middle of the night sometimes wake me (i'm a light sleeper).. Is my house sinking or in danger of collapsing? I'm concerned and not sure what I should do... would insurance cover this kind of problem?