so confused... what should I do?

I had a miscarriage in February and I was devastated... after I had one I got obsessed with trying again... well may we had sex and then around the time AF came it only lasted 2 days.. so then we didn't do anything then.. so then I waited for June to come around AF showed up on time but only 2 days and spotted on the 3rd and I was done. Both months weren't normal so didnt have sex then either... now its July and AF was supposed to come and never showed I am now on cycle day 39. my periods are always regular sometimes AF lasts for 35 days.. but I've never had one go this long... I took a cheap dollar store test this afternoon and it was negative... idk what I should do. should I be worried? could i be pregnant and still have negatives? im full of questions and no one has answers... please help.....