What Causes No Periods From 3 Months?

hello... i have endo, but my periods have been thrown off lately.. i have missed my period 3months now, i have brests that are so sore i couldnt sleep this morning.. i am always tired, and i threw up one morning.. ive taken countless tests, 5 positive the rest after negative, dr.'s do not know whats wrong with me..last night i even had a white milky sticky substance come out my nipple? help!