He asked me out a while ago and I said I would think about it. We talked for ages every day after that and aren't 'officially' going out but he has referred to me as his girlfriend and told me how much he loves me.
Not long after we started dating, he was able to tell me everything about him, including things nobody else knows about him. It's really obvious he loves me and he told me, further into the relationship he would want to have sex with me and asked if I was OK about it. He said if I had any doubts it would be fine and he wasn't going to make me do anything I didn't want to.
He seems perfect, he cares a lot about me and gives up all his time to be with me but I'm not sure if I actually love him and sometimes I wonder if it will work. But when I think about it I can't see any reasons as to why it shouldn't but I still get doubts. Is this normal?
YES. This is normal. If your conscience or common sense is telling you something is off, then something is off. Do not ignore it.
Sometimes, the guy who is absolutely perfect in every single way just isn't the right one! And while it kind of sucks, because it would be great if the perfect one WAS the right one, there is no way on this earth you should settle just because you can't find a reason NOT to be with him. The fact you're searching for a reason is reason enough.
You need to step back from this relationship. While this guy may be perfect, he is way more involved in this relationship and has more feelings towards you than you do towards him. Be fair to him and back off for awhile. Tell him you need to figure things out because you want to make sure he's getting what he deserves out of the relationship. And, if you can't give it to him you want to be honest about it.
Really. You could seriously end up hurting this guy is you don't step back and get your feelings in order. There is nothing wrong with you not being able to return his love. That happens sometimes. But there is definitely something wrong with you leading him on and not being upfront about the fact you're not sure you know how you feel. It might hurt him to hear it, but it's the right thing to do.
So step back. Think a little more. And then do what you have to. Maybe you'll figure out, during your time apart you can't live without him. ... or maybe you'll find out you can ... and should.