What does my dream mean?

I have had similar dreams in the past, but lately I have had them even more. They aren't always exactly the same, but in all of them I am in a tall building, and the higher I go, the more the building wobbles. I have trouble going up the stairs because I am afraid that the building is going to collapse. Some of my recent ones I've been in a version of my old high school and/or college (sometimes combined). Although it doesn't look exactly like those places, but I know in the dream that that is what it is. I'm usually going up to the high floors for a cl or something but can't seem to, or am just afraid once I am there. What's that mean?