Is it possible to have a negative HPT at 12 to 16 weeks pregnant??

Okay, so about 5 days a go I took ONE HPT from the Dollar Tree. Its the only test I've taken and it was negative. Id be somewhere between 12 and 16 weeks pregnant. I haven't had a period since February. I bled it March, but it was MUCH MUCH different than my regular period. No bleeding at all since then. I should say too that my periods are usually regular and Im not under stress or anything else. My signss are: Missed period cramping mildly for a few months sore boobs but not nipples (off and on) I pee all the time!! constipation gas BAD bloated nausea dizzines, especially if I stand up to fast heartburn very sensitive to smells no apetite all I want to drink is tea. Its not really a sign but I find it odd. So is it POSSIBLE to get a negative? People keep saying "oh it would have shown up by now". Well for one ive only taken one test. And for 2 isn't everybody different? Should I buy a different kind of test or what? Please help. Thanks in advance.