BASED from the information, you have irregular menstrual cycle for long time now, and history says that 4 doctor's say you don't ovulate still you have 5 children, that put me in dilemma, how to answer this question , still I will try to help you in one or the other way.
YES the nausea
and food aversion is commonly seen in pregnant patients but it mostly come with in a week of implantation
due to increase HORMONE - HCG
, which can be detected in URINE after 10 days of implantation so if you do check for URINE -HCG and test comes negative we can INDIRECTLY say that the nausea and food aversion is due to some other reason (like, gastritis
viral) But for that follow the advice.
Best way to detect that you are pregnant / not will be the URINE PREGNANCY
TEST KIT, (its a kit which is available over the counter and you have to follow the instruction how to do the test simple by urinating on that stick) If it says negative at this time , try to use it again after 7 days from now and it that is negative that will SOLVE your issue even with out going to the doctor.
HOPE IT HELPS.