How early is too early for a blood test!

I have a drs. Apt tomorrow my period is in 2 weeks. Supposed to anyway. My husband and I have be diligently trying literally bd every day sometimes twice daily if we are lucky. Would a blood test at my drs appointment tomorrow to see if I could be pregnant be too early. I have yet to have a position ovulation tests so I was curious if blood work could detect it faster? Any thoughts on this?!