Can you get a false negative?

I had an HSG on March 4th, then got my period a week early in March, it was abnormal too. Extremely light, not even needing a liner. Then this month I am 5 days late and sorry breasts. I dont have any other symptoms, but I never get sore breasts with my cycle. I took 2 hpt's in March, both were negative. I took another a couple of weeks ago, and another just last night (4days late). Is it possible to get a false negative still? I dont know if I should contact my obgyn to see if we can get a blood test. I dont want to seem crazy, but I am wondering now if I might be.