Ok me and my girlfriend are 17 years of age and she is on birthcontrol (the pill). She takes it every single day at the same time, the only difference on this cycle was that she had to take antibiotics for a throat gland that got swollen. We had intercourse once since her last period and I pulled out way in advance to ejaculation (well aware of pre-cum). According to her schedule on the package she should have started today and she has all the symptoms of starting she just didnt today. Should I be worried or should I give it a few days or what?