I also was suffering from somewhat similar symptoms recently. I felt really tired, bloated, back and/or stomach pain, nauseated for weeks at a time which               would often lead to vomiting. After a year & a half of feeling awful; like I was recovering from the flu, I told my Dr. & he ordered a Gallbladder Ultra-sound. Turns out, I had Gallstones. So the Dr. then scheduled an out-patient surgery to have my Gallbladder removed. Three weeks later I felt like my old self again....no more nausea & vomiting. Maybe you should ask your Dr. if he thinks you having a gallbladder ultra sound is a good ideal.  Good luck!!