Going on 6 weeks late, 2 negative tests, spotting and all the symptons?

I've had 2 pregnancies. I knew with both that I was pregnant well before I took the tests. I must of had to pee every 10 minutes regardless if I drank something or not. And with the 2nd one- I just could not drink beer. I had no taste for it and that's usually not me. The tests only confirmed. This one, if I am pregnant, it's totally different. It's throwing me for a loop and getting my husband totally excited. I'm 5 1/2 weeks late, I've had period like cramps for the last month. Ever since about June, my periods have been very irregular. Yesterday, I started spotting brown stuff... since it's looked like a very light period. My breasts are tender and and full. My stomach has hardened on the top. I've been completely emotional (everything makes me tear or cry) for the last 2 weeks and yesterday, I got so nauseas I wanted to vomit. Everything tells me I am pregnant, but 2 tests are saying otherwise. I plan to take a 3rd in the morning because that's when your urine is supposed to be most concentrated. My OBGYN appointment is not until Thursday.... that's too far away!!? LOL. I hope I'm not forgetting anything... Hmmm. I'm guessing what it all comes down to is I'll have to wait for my appointment. But if any of you have been through this, please let me know!!!!!