I'm really uncomfortable with the behavior of the top executive in the office

Girls, give me some advice! The assistant manager at work has seriously fixated on me, constantly calling me into his office with some excuse or another, like "let's have coffee" or "let's talk after work". I have no idea if I’d get fired if I complained, or if he would get into trouble. On one hand, it's really hard to find a job these days, but on the other hand, I'm feeling sick to my stomach; I’m literally crying on my way to work every day. I really don't know what to do.