Should she take prostinor again?

My Girlfriend stopped menstruating on Thursday. We had sex friday night, and Saturday morning, she used prostinor on Saturday, but then again we had sex on sunday. We don't know whether to use prostinor again and didn't, but now she feel like she might be pregnant (what are the chances... she's being urinating frequently). According to her glow calendar (25days cycle) she'll ovulate on the 11th of May.. however he last cycle was 23days not 25days so the ovulation date my be different (earlier) by at least 2 days.. is she pregnant? Why is she urinating so frequently?