Pregnancy symptoms?

Hey guys, I was wondering if anyone could tell me if they were badly constipated before they knew they were pregnant? It's been happening for about a week now, and has never been this bad. My partner and I had sex a lot when I was due to be ovulating which was around the 6th November. My period is due in about 4 days time and I can't help but feel like it's not going to come this month. I can usually tell when I'm going to come on but this month I haven't had any of the signs. I keep feeling randomly sick and have bad headaches, too.

Any advice would be great!