Missed period

I've been married for a month now. My husband and I had a lot of sex on our honeymoon. I stopped my birth control pills in April and my periods have been regular ever since. I get them around the 9th of every month. But as of right now I'm 9 days late. I've NEVER missed a period ever! I took a test last Friday and there was a very faint positive. Waited a few more days took another one and was negative. Waited one more day and took another one and I was also negative. I have an appointment Monday for a blood test and I'm really scared their going to tell me I'm not pregnant. Which that's okay, it's just the fact I still don't have my period which means something else could be going on. Am I psyching myself out? What do you guys think?