How to break up with your best friends?

Right now I’m a senior and I’m mentally exhausted from being with my best friends. I’ve turned into someone I don’t want to be and now that I realize that, I’m still not being who I want to be because I don’t know how to drop them so I’ve been being fake, all year. I have all but one class with them and one of my classes I have with just them and my teacher. I’ve also already stopped hanging out with them outside of school except for every once in a blue moon and just spend my time with my boyfriend. It’s to the point where I’m seeing myself get jealous when he has other people to spend his time with, because for me he’s all I have(I get that that’s crazy and controlling so of course I don’t say anything, I know I’m wrong for feeling this way). While my mental health has been going downhill I’ve stopped talking to any other options I’ve had for friends which is yet another thing I’m in the wrong for, I feel the need to apologize to them but idk if I should just go back to normal with them. Another problem with them is I can’t just join their group without actually leaving mine. The people I’m “friends” with now will say something and I’m gonna have to tell them the truth. I just don’t know how without getting laughed at or without petty fights starting :(

All the guilt from being fake and just not being me and upfront is really tearing me apart right now and I don’t know what to do. I just want the year to be over and for college to start so I can make complete new friends