Is something wrong with my sex drive?

I have dated my boyfriend for over four years. We used to have sex all the time. I went through a bad birth control year where I didn't want to have sex. We would about once a month. After changing birth controls, I want to a little more now but not nearly as much as I wanted to before and now when we try it doesn't even fit - we've tried lube, foreplay, condoms, no condoms and nothing seems to work. What do I do? Is it me?