I need help please!!

I have not started in about 1 month and a half we have been trying to conceive for 9 months and still nothin and I have been getting real sick my breast have been real sensitive and I have been tired and craving stuff really bad and I don't know weather I should take a test or not I took one about 2 weeks ago and it was negative how long does it usually take? should I go to the doctor and see what's wrong with me?