Touched at work??!!!!?

There is a man that is a janitor where i work and he is starting to creep me out. Okay, he keeps looking at me in a yucky way that makes me feel uncomfortable and saying things like what are you gonna get me for christmas, and stuff like meet me for lunch. Well I blew it off becuse he is kinda slow and you can tell, so I didn't wanna say anything. So today as I was getting on the elevator he came on it too and we were the only ones on there. As soon as the door closed he came across the elevator and put his hands on my shoulders and started maging me. I jumped away and told him to stop and he just smiled. I don't like him doing that. I have seen other women letting him do that and that is why I have not said anything becuase I'm scared that they will get offended. I am just sick of the way he looks at me and now he's trying to touch. I am 21 and married. The thing is I just got the job, and I don't want to start it off by turning people in that has worked there like 20 years when i just started! I don't know what to do. I'm actually almost crying now. Other people never have a problem with him and I am scared they will think I am over reacting. What do I do??