I had one test say no on a Saturday and then on Thursday it said definately yes. I like First Response. It has never told me wrong ;-) I would give it a couple of days and then take one. My experiences with pregnancy never had bloating as a symptom, but everyone is different.
Even though you dont want to take another pregnancy test because you are afraid of the negative you still really should. If you are indeed already pregnant you should be taking prenatal vitamins already for yours and your babies health. It is weird that you missed a period. A friend of mine never got a positive pregnancy test at home, even after she had already found out at her doctors. Good luck to you and I hope you get your positive =)
I say take another test. If you had one that looked positve, then there is a chance it is. Some tests are more sensitive than others, and sometimes the urine is more concentrated than at other times. With your period being that late and having some symptoms, it is a possibility that you are pregnant. If you are not pregnant, then I really think that you should go to the doctor because these things can signify other problems. So, make it easier on yourself and rule out pregnancy. Hopefully it will be positive!!! You can post a pic of your test on here if you are uncertain. We all have super duper HPT eyes!
Good luck and super sticky baby dust!