Try gettin first response test
I had a false positive test once due to an active cyst. I would see your ob and check all your hormonal levels. Are you trying to get pregnant? If so you may want to see an RE; they can make your cycles more regular.
Ok, I misread the question. It was the digital that said pregnant. Digital tests rarely give false positives, so my response has completely changed. I would now definately see the Dr. for more bloodwork. It is possible that this is a new pregnancy and the digital was more sensitive then the Wal Mart brand. It is also possible that the way the digital test was stored is giving you a false positive. Best of luck to you.
the digital said pregnant && the dye said negative
Well, the best thing might be to see the Dr. again. Personally, I would suspect this is not a pregnancy. I have found blue dye tests to often show a ghost line that can very much make you believe you are pregnant...I've had it happen to me. And if you have not had a period since April, June had bloodwork done that was negative, I think it is somewhat unlikely as it sounds like you may not be ovulating for some reason right now.
Of course, pregnancy is always possible, so best to have it ruled out, then perhaps ask your Dr. to further investigate what is going on.
All the best to you.