Thank you everyone for your replies!! As of today I'm 9 days late. I have used clear blue on the 25th (1st pee)and got a positive (faint), I used clear blue on tues afternoon and got a neg. used first response on the 28th (1st pee)got positive. Used clear blue on the 29th (1st pee) got a positive, dr's test came back neg (probably 3 or 4th pee of the day). My last 4- 5 periods I was getting spotting a week before my period but I've had nothing at all yet. Normally I would have had some spotting around dec 14. It may be wishful thinking but I definitely feel pregnant.
I forgot to come back and see your answers. So 9 days late should reveal a very positive pregnancy test. In other words, you should have tested positive at the docs office. My guess (and I am sorry to say this but I want to be honest) is that you are experiencing a chemical pregnancy or a blighted ovum. I had several of these while trying for five years to get pregnant with my second child. I also had some late miscarriages as well. Both are very emotionally painful.
However, I could be dead wrong and you could have implanted late (maybe ovulated late). So take a pregnancy test in a few days as suggested above.
If you have spotting before your period actually comes, it sounds like you may be low on progesterone. I don't know how long you have been trying to get pregnant or your age so I am not sure if it is time to see a reproductive endocrinologist but I will tell you this: if you think you have Celiac or NCGI, get tested and get to the bottom of this. Both of those diseases cause miscarriage.
Also, if this is a chem pg or a blighted ovum, there is some good news from this, you know you can get pregnant. That is a a good thing but now you need to take care of this gluten issue as it may save you a lot of heartache in trying to get pregnant in the future.
I am sure there are others with more advice. This is my two cents.