Once upon a time I had service... now I do not

So, I work on the first floor of an office building. This isn't an ideal place for cell service. I in fact switched over to Cricket for the fact that the people around me that would get any kind of service at all, were with Cricket. So after switching I've had mediocre service for the past 8 months. 1-3 bars, which wasn't great, but I could stream youtube, podcasts, surf the web, text, answer phone calls and it was better than anyone else had from what I had noticed. For whatever reason last Friday the service plummeted and I wasn't able to do anything at all inside the building, even in areas I use to get even better service than at my desk. A few people around me who use to get no service at all with other providers are now getting service. I'm just wondering that has anything to do with my loss of service. I'm on my second day of having absolutely nothing unless I stand outside in the freezing cold, and even then nothing comes in unless I stand far enough away from the building. I live in West Des Moines, Iowa if that helps at all. I figured maybe there are tower issues? but the service is fine outside of work, so that is not likely.