~sorry this is quite long but it would be much appreciated if you girls could take time to read this and feed back with your initial thoughts / advice ~

Me and my boyfriend had sex about 2 weeks ago (we used a condom). I was due to get my period about 5 days ago but i still haven't got it. Because it was my first time having sex I became concerned as to why my period is late, taking into account I've always had a 28/29 day cycle and never had any late periods or problems occur when it comes to menstruating. As I live with my dad and younger siblings, there are obviously no pregnancy tests to hand in the house, so I took to Google to find ways I can test it at home. For better or for worse, I took the bleach pregnancy test. I've taken it multiple times, all of which the mixture has fizzed and given the "positive" result. After I did this I told my boyfriend and the next day we went and bought 2 pregnancy test sticks. I've taken both of them and they've both given a negative result saying I'm not pregnant. Because I'm putting my trust in the store bought tests over the homemade tests, we both breathed a sigh of relief that I'm more than likely not pregnant, but this still leaves the question as to why I haven't yet got my period. I'm experiencing sharp , (extremely painful) stabbing pains (which feel like period cramps) in the areas id usually get period cramps but mainly on the left side of my lower stomach. It's like I've got the symptoms of a period but no period blood! If anyone has any ideas what this may be or any advice as to what I should do next it would be much appreciated x