Help!!

Hi im going stir crazy! Im 2 months without a period now about 4 days late on my 2nd month. Ive done several tests and all negative but having some werid symptoms like massive increase in appetite nausea, not actually being sick but like waves of feeling sick. Also strong cramps in my stomach and inside feelings funny. The feeling inside is almost like wen u r having a smear test. The doctors have told me to test again each week till i come on my period and they will send me for ultrasound if i dont come on my period soon so i dont know wot to think.... we have been trying for about 6 months but i dont want to get my hopes up. Has anyone had similar?