Pregnant?? late, crampy,hungry, morning sickness..?

Lately my periods are abnormal...they were usually like clockwork. Anyway- im late, i have been experiencing vomitting whenever it feels like coming up-it does...a little cramping, heartburn like i never knew, and eating!! For an example- i dont eat sweets normally-but i have had a half of box of cream filled coffee cakes (3 pks=6 coffee cakes)today -alone.. that is nuts!!! and GROSS!! Now i have taken a test this morning and it appears to be negative- however im not really sure when im due for a period since they have been out of the norm- but the doctors office thinks it s/b between 4/25-4/28...am i testing too early?? or maybe not pregnant. I have been having unprotected the past 2 months- and yet we havent seen a positive preg test. Would i eat like a preg person or have symptoms and still show neg on a test?? i thought these symptoms were from HCG- and if HCG was detected-wouldnt i have gotten a pos home test this morning?? Anyone with insight-please help- thank u