Needing kind words of wisdom

Recently me and my boyfriend of 2 years have been going through a rough patch...sort of. It’s mostly just me. I am afraid I don’t feel the same as I did once before. But if I think about him and go through our pictures I still feel like there’s something there. I’ve always considered him to be the one I am going to marry so naturally feeling this way has kinda sent me into a spiral of worry. He knows all of what is going on and is being so supportive. I just am afraid. But if I’ll do anything to go back to how it was not too long ago. I was wondering if anyone had any advice to get out of my head and stop worrying about everything? Or things they did / experience in a situation similar to mine? I don’t want to just give up on us but I feel lost. I know time is my friend and I don’t need to rush myself to make a decision and worrying about it is making it worse but it’s easier said then done.