Girlfriend has pain day after losing virginity;

my gf and i had sex for the first time both losing our virginity 2 days ago, shes paranoid bout being preg cuz the next day she felt sharp pains in her lower abdomin and felt a little sick but it went away 2 hours later, then in the afternoon it came back for like 10 min and went away. I also am sick so maybe she just caught a sickness from me but idk why she would only feel sick randomly and then randomly go away.

i used a spermicide condom also and we had sex 16 days after her last period if that matters and she didnt bleed either