The first thing you should do is call 611 on your phone and reach out to the advanced tech team. That way the issue is known. This forum is mostly comprised of other users like yourself and although I can suggest alternatives to allevate the issue I can do nothing to fix it.
In the mean time until it is fixed you should connect to the campus wifi and set up the wifi calling on your device if you have not already. It will allow you to use any internet connection to send texts and place calls.
However for the long term I would file a ticket and explain in as much detail as possible what has been going on so that T-mobile engineers can attempt to resolve the issue. Although something could of happened that makes a issue.For example, if a new building was built that blocks your line of sight to the tower effecting the signal or something along those lines.
I apologize in advance if this is something you did not want to hear but its just one of those things that just happen in life. Let me know if you have any questions i'll attempt to help as best as i can.