What would you do?

Last week, this older man was sitting out in his car outside my home on the street. I went out and asked if he needed help and he said "no, I do need help with my pants though". I was confused and laughed and walked away. It was creepy. I left my home to go to work. I come home later that night and my front door was unlocked, which was odd. My drawers were open and I'm almost  positive I wouldn't leave them open....I notice my bed sheets weren't straight like I always leave them since I'm a little OCD. I go to bed. I get up again and this man is out there. It almost looks like he was masterbating in his car but I was late for work so I didn't investigate. Would this cause enough worry to call the police? I don't want to be turned down by them and look stupid cause I do worry a lot about everything. I think this man is "stalking me" but I have no idea how he would of had my number. Maybe it different cases, I don't know. 

-I'm 27, not married, single female. Havent dated in years so I don't think it's just some crazy ex because I've only dated two men and both are normal professional men who do not even live near me anymore.