maybe I'm crazy still lol

Okay so.. I had sex in October, but I also had my period in October. But it was literally 5 days late, and it wasn't how it normally is, it was watery and pinkish for like 3 days? 
I took i dont know 5 tests? And they all came back negative except for one with a faint line. 
Well.. I didn't get my period in November. 
Do you think it could be stress? 
Or something else? I'm paranoid so bad.