Am I Pregnant or What's Wrong?

My fianc� and I are not necessarily trying to conceive but if it happened we wouldn't be let down. so with this being said, we don't take any extra protective measures except the pull out method. Now, I was due to get my period on the 15th of this month, but it didn't come, so that makes me 14 days late. one of these mornings during this time, i did wake up and throw up for no reason at all, i have had alot of headaches that last all day, cramping as if i'm going to get my period, but nothing happens, my breast haven't really been that tender until today (14 days late) and even then its not excruciating. i've been very moody, kind of craving stuff, having weird feelings in my pelvis, and horrible constipation, acne, and bloating. now with that being said, i have taken 2 tests, both negative. So am I pregnant or just having a weird period month? i have a doctor appt on Tuesday so i'm really just looking for incite! thanks!