Very Late period all tests negative

Hi, We recently started to try for a baby. My cycles since Oct 2012 have been from2 28 at the shortest and 37 as the longest from jan-feb. my average is about 30 days. I took a LH test on march 22nd and it tested again about 36 hours later and it was negative. We had sex the day before LH + the day of and the next two days and then again that weekend. i started to have pms type symptoms starting around April 1st but it seemed to Come and go without getting my menses. I'm now on day 37. I I have used preg tests daily two ept one clear blue and many dollar general brand. Every day it's negative. But the thing is that I have been nauseated the last few weeks off and on. My breast are tender my nipples are very sore and longer and bigger, I've had a shooting pain in my breast to nipple a few times, and something like that in my groin a few times last week. Im very concerned about not having my period yet. Can this mean I'm infertile or becoming so at 28? I was pregnant once at an early age and was pressured into aborting it (was the right thing to do looking back) but could this have made me infertile? Could I be preg with all tests coming out negative? Please help ASAP! The anxiety over it now I'm worried might prolong this. Thank you so much!