advice..

so, i'm late. very late. i have irregular cycles, but nothing like this.

my last period was march 22-26, a normal cycle. i had unprotected sex on the 6th of April, he did not pull out. i was to expect my period at the end of that month, nothing. i grew symptoms of fatigue and full boobs, appetite. i took 3 pregnancy tests a week/ two weeks after my missed period, negative. could i not be producing HCG high enough for a positive? maybe something is wrong with me.. i've not really stressed this but if i'm not pregnant i'd like to get my period, it makes me feel unhealthy. has anyone gone this long and come to find out they were pregnant? i have a new prescription of birth control, should i start it? sorry for all the questions. i'm so confused, please comment.