12 days late and faint line

So I'm 12 days late today. My period was supposed to come last Sunday. My last period was on Feb. 16th.. I'm usually NEVER late. If I'm ever late then it's usually one or two day max late. I took 3 hpt and it all had a faint line. I checked it within the 5 mins I was supposed to wait. I've been feeling very nauseous for the past week.. Help!!! Has anyone gone through this? I'm planning on doing a blood test but I'm afraid of it coming out negative. I really would like to have a baby this time with my hubby :)