I slept with a girl last year. Now shes pregnant and passed all the tests including stds. Is it possible of still getting an std from her?

I think i got genital warts from some chicks in vegas when I went there with my friends I only slept with 4 girls and I am not sure who I got it from or that I had it at all.

Then all a sudden my girlfriend got genital warts and got all mad at me. Like as if I was supposed to know.

how can she be mad at me?