Help!

So I had protected sex several times with my boyfriend for two weeks when he came to visit. We used condoms and the pull out method while wearing condoms. I was afraid a condom had slipped during one of our intimate moments, so I took Plan B just in case.

I got what appeared to be my period and on time. It was shorter by a day than usual, and I assume this to be because of Plan B.

After getting my period I took THREE pregnancy tests, all on different days. All pregnancy tests have come out negative.

Is it safe to say that I am not pregnant?