4 mths pregs last child is 17 yrs, i am 38 having lots of pelvis pains like crazy.Not eating much feeling blah?

Do not know what to do. I used to go gym but now with the pain my movements is limited going to work as usual do not know what to eat anymore. When I drink water I feel upset, milk - upset, do and cannot eat meat and all my favorite foods that i used to eat like pizza, cake, lasagna, chocolate, cereal, ha cannot eat. All i do is eat bananas, apples, drink juices, eat whole grain breads, fish. Cannot go to dinners or lunches, fart is foul, belching like a drunkard in a bar and pain in my pelvis. Can sleep for three to four hours in the night. Wow do not know what to do again. Taking tonic and iron pills. I have 5 months to go sigh...