Not sure about marry him now...help?

I have been with my fiancée now for five years. I do love him and though we've been through tons of hard crap together we have made it out on top and are actually a lot better. Well I finally started planning our wedding for this November but I am not sick every time I think about marrying him when before I was excited and happy. I don't understand why I feel this way and I know it's not cold feet. It's like down deep in my stomach I feel like I'm making a huge mistake marrying him....we have a 1 year old together and all but I'm just not sure about this anymore. Idk what to do. And I can't talk to him about it because he wouldn't understand and isn't easy to talk to about this stuff.