My parents are ostracizing me?

So I’m a 17 year old girl and a little over a week ago my mother and I had a heart to heart conversation. For some background on this, about a year ago my brother did some bad things and it put a strain on our family, in retaliation I had sex with a few boys just because I didn’t know what else to do for validation. Flash forward to now where I’m in a happy, healthy relationship with my boyfriend. Him and I still have sex but it’s out of love not lust. I told my mom everything because I thought she already knew or at least suspected. Directly after I told her, she was cool and calm, then she ignored me for the next 3 days. She keeps saying “I don’t even know who you are because you lied.” And “If you want to be an adult and have sex, I’ll let you be an adult and leave you alone.” I had my first job interview on Monday and all I wanted was her support which i received none of. My parents are Christian and so am I but is my mom in the right for not talking to me and not letting me serve communion and church because she found out I sinned? On the other hand what is the Christ-like thing to do? What should I be doing to mend the relationship with my mother who won’t listen to reason?