I don't feel like making out

so it used to just be every once in awhile but the past two times my boyfriend have hung out, I have absolutely no urge to kiss or make out with him. I am starting my period next week so maybe that's it? I love him so much and he's definitely hot and I'm attracted to him but I just don't feel like making out with him. It's starting to make him feel like I don't like him and it's starting to bother me because it's almost like this numb feeling that comes over me. I have been open and honest with him about it which I honestly feel is good it's just hard to explain why I feel this way and it also makes me feel like I should question him and I but I don't want to because I love him so much and I really do want to be with him. It's just weird and I feel really weird feeling like this at 19 when people say your sex drive is supposed to be through the roof.