Should i tell my mum?!

I want to talk to my mum about things that have gone on ! We are quite close , my ex boyfriend cheated on me , ofc I was really upset , and I told her that me n him did stuff (oral sex) and that I felt like a mug... I was really scared to tell her , she wasn’t angry but she was disappointed in me , however now after telling her she has lost trust in me .... I am now in a relationship with someone else , we did have unprotected sex , and I have taken a few pregnancy tests (all come back negative) , me n him are ready to do it again n stuff , we both don’t regret it! , however I want to go on to the pill or something like that just to be more careful... I could tell my mum anything we was talking about getting the pills months back because my periods are too heavy n stuff , I said what about the pill n she said u would only go on the pill if u have had sex ..... I just don’t know how she will react.. please can people give me advice !! Thankyou for reading this n helping me much appreciated xx