Confused?!

We've been TTC for 7 months. My period was 21 days late and started today. I took a few pregnancy tests and all were negative but I've had/still have a lot of pregnancy symptoms. I have an appointment set for the middle of the week for a blood test but with my period showing up I don't know if I still get the test done or what. My period has been a lot different than it normally is too. A lot less than normal but darker and horrible cramps that I never get. Is it just a weird month?!