Is it normal if he makes me this shy or reserved?

When I met my bf, I just became single and one of the reasons why I became single was because I wanted to be myself again without restrictions or anything. He made a move on me because he did find me attractive but also cause I was a lot of fun and carefree. Eventually we got closer and now were serious; its been over a year. However, in the beginning, I was still myself but then gradually I just started caring so much about how I came off to him and began watching my every move. I think because I just liked him so much and I liked what we had, I wanted everything perfect. Its been like that forever now and Im still dealing with it but now its even more frustrating cause were more serious so I want him to know the real me, like the person he first met. But it is SO hard to just be me around him now. I feel shy, reserved, scared, nervous, anxious, worried, timid, all these things that he probably doesn't enjoy since he has tried to make me losen up a few times before cause I guess thats who he remembered he met. I try to losen up but its just not in me when Im with him. Its so annoying, I wish I can just be myself the goofy girl he met and the goofy girl I really am. Ive asked during some of our conversations why he likes and he tells me cause Im "goofy chick" and I find it relieving he still looks at me like that. I don't want him to see me like this bore. But what has happened to me to not feel like myself around him? It has to be more than me caring about how I came off to him...before I could understand but now I realized he doesn't want that type of girl, he does enjoy my silly side so Im trying to get back to that but nothing is cooperating. I don't get it and I want to find out why and start losening up cause were getting serious and for someone to not be themselves in the relationship is not a good thing for the long term.