Is it normal to not no if you like someone anymore but wuld die without them

Ok so I have anxiety, and one night my girlfriend told me to listen to this song Perfect Two by auburn and for some reason I felt bad I don't know why for sure. At first I thought that it was because when we first started dating I asked her if she would care if I smoked weed and she said go ahead it's your life I can't stop you and I called her one day because my friend ask her for nudes the night before and I called her to say sorry about that but I was on a nicotine high so I said I'm so buzzed. And then there was this other thing where I stated to talk to this other girl a grade lower than us and text her I would say talking to this girl. And in this song it says the you can be the peanut butter to my jelly and a whole bunch of things that go together but it made me sad and I started crying. I told her about this and she said she loves me more than anything and that she wanted to be with me forever. I felt the same way but than I started thinking what if I don't love her back and my anxiety kicked in so now it's stuck in my head that I don't love her and it's killing me inside. I am so love high when I'm with her that I feel like I'm gonna pass out but when I'm with her I just don't know about us. I'm in 8th grade and I'm relationships don't usually last long by we've been together for a while and I don't want it to end