Neg. preg test...but I still feel pregnant.?

Ok...so my period is now 9 days late. On day 7 I took a CVS brand pregnancy test. I thought it was positive because I thought I saw a faint line in the positive area. BUT that was after the 10 minute allowance. So I thought it could be an evaporation line. I took another one a few hours later and no line... I called the company and they said that I may not be secreting enough of the hormone. and to retest with a better brand with my first mornings urine. I bought Clear Blue Easy +/- symbol one... it appeared to be negative until after 10 minuted when the top part of the plus symbol appeared. BUT only the top. My husband just umed that I am not pregnant and it's all in my head. But 3 days later, I still have not started my period and while in the shower have noticed some cervical discharge...mucus like...with strings of blood in it. But no real period blood. And my ache now. I am scared that I really may be pregnant. But I can't stop doing my job (taking xrays) until I know for sure. When can I retest? What do you think? Are these signs of a period or a pregnancy?