So confused

So..I got blood work done a few days ago...said that it was negative.

Is it possible for blood work to be off? Or that I got blood work done too soon?

I’ve had sore breasts, heartburn, lower back pain, fatigue, and frequent urination for about a week now. Usually I’ll get sore breasts for about 1-2 days before my period.

The last time I was pregnant I had the same things.

HELP!