I really need some reassurance

So I don’t usually do things like that, but I had unprotected sex with a guy I’ve liked for a while, I took a plan b the day after... it’s been 3 months I have had my period as usual and everything (I think) so I don’t know why I keep thinking about it but I keep freaking out that I could be pregnant to the point of pressing on my stomach to see if I can feel anything. Well about a month ago I took a pregnancy test (from the dollar store) it was negative, this made me feel better for a while. But I keep going back to thinking about it! This past two days I’ve been feeling so dizzy and weird in my stomach and it made me think about the possibility of being pregnant again?

Can you guys just reassure me that there is no possible way that I could be pregnant? I really need this?!