HELP. Having all the signs of pregnancy but can't get a positive test??

I've been having all the signs of pregnancy but I can't get a positive home test,I keep getting negative results, or I get a pink line that's to faint to be considered a true positive. Period was 3 weeks late, then spotting, its only been two weeks since then and I'm spotting again. I'm getting headaches all the time, queasy everytime I eat, super bad hot flashes, itchy tender breasts(which are getting bigger), tired all the time, small painful twinges occasionally around my uterus and pelvic bone....and I keep getting these weird fluttering feelings in my uterus.......I'm going a little crazy because I can't get a positive urine test. I would be 5 or 6 weeks pregnant right now so I should be far enough along to get accurate results...has anyone had this happen to them?? please comment, I could use some feedback or advice