Hi Aleia!
I'm sure you have a ton of anxiety right now about having your diapers discovered by your mom. Don't forget about the unconditional love that a mother has for her children. You might be surprised how understanding she would be if you told her the truth. If she hasn't said anything to you yet I doubt she will. If she does or you just feel the need to discuss the matter I would not lie about it. If you really want more privacy maybe you should look for another place to live.
Good luck!