Advice for college LDR

really need someones advice, me 18 and my girlfriend 18 have been dating since middle school we went through all of high school together and now we’re in our first year of LDR in college, she goes to school 5 hours away from me and she has always loved me unconditionally, has never done anything to make me think I can’t trust her, but for some reason when she left I was hit with a rush of emotions, I feel insecure about our relationship and I constantly think she’s doing something behind my back when deep down I know she’s not the type of person to cheat. I understand that these feelings are coming from my own head but it feels like it’s starting to control my life, all I think about is what she’s doing, who she’s with etc… i don’t want to smother her with how I feel because I understand she’s now in college and she needs to live her life but I don’t know how to deal with the feelings I’ve been feeling. I really love this girl and I want things to work I don’t want to be the one who ruins the relationship, I’m going to school where she goes next year but I want to be ok and not jealous for right now, if anyone went through this please give me advice, cuz the only advice I get is advice from tik tok telling me my gf is cheating on me 24/7