Hi, my husband and I have been trying to get pregnant and I have been 10 weeks late on my period. Of all the home pregnancy test I did one came back positive, but all the blood tests were negative. My problem now is that my period started last night, first with some spotting, but now it is heavy. I am 25 years old and used the pill for 5 years and have been off the pill for about 4 months now. Am I experiencing a hormone imbalance or something?

I believe your body is trying to adjust itself so yes it could be some hormonal imbalances..

Have you been to a doctor? I was once told that HPT result can be wrong if it is negative, but a false positive is 1 in a million. I suggest you go to a doc as you were on pills for such a long time. I strongly feel it's harmonal imbalance.
Best wishes