you can get a blood test done
hpts are normally correct though. sometimes women never get an acurate result on an hpt but a blood test will be acurate. the hpt should be giving you a acurate result right now. but you could get a blood test and then if its nag talk to your dr about why your period is late
could be stress related. sometimes if your young then you get iiregular periods. its normal and it can happen
hope you get it figured out!