Thank you so much, Sierra! I figured it was something simple!

Edit: I changed it to changeLotZoning dorm and when I moved my sims in, it went right into build mode with limited building options. I changed it to a residential lot and I had full building rights, but my sims were not there! Any idea on what I did wrong? I thought changing the zoning to a dorm fixed it, but my sims are not there! It shows that they live in that dorm, but when I enter the dorm, it's in building mode. I hope that makes sense...
Apologies if I'm misundertannding the situation, but did you change the zoning while your had your Sims on the lot?
That's a no-no.
Move the Sims back to the bin and try moving them back into the lot only after you have finished your design work and after setting the zoning to what you want it to actually be..
Regarding changeLotZoning -- it functions best if you use it on (a) lots unoccupied by any of your Sims and (b) if you exit back to the 'hood after changing the zoning and then re-enter the unoccupied lot to do whatever you need to do under the new zoning.
To get full building options when creating/altering dorms, you don't have to change the lot to residential at all. While in the unoccupied dorm, use:
boolprop dormSpecificToolsDisabled false
to enable all building/buying options.
Change back to:
boolprop dormSpecificToolsDisabled true
when done with your construction/decoration and then exit the lot.
When you move your Sims in after that, the dorm should function normally.
It may be the case that the specific dorm involved in your question is now toast, but moving the Sims out, making sure the zoning is correctly set without them in the lot and then moving them back in might kick things to normalcy.