My symptoms are similar. I have always had random bouts of minor nausea, but from June-mid August it occurred once a week and would last all day. Previously it had never made me actually throw-up, but from the beginning of August to the end of September I threw-up at least once a week, and was very nauseous for about 5 out of 7 days. At one point I threw-up 3 times in one week. I was put on some kind of medicine to take at night to help with nausea and sleeping problems, but it hasn't helped at all.
Since the beginning of October the nausea lessened to about 3 or 4 days a week, with only 3 or 4 bouts of vomiting for the whole month (the last time was October 16). Now it has been coming back, as well as a strange pressure in my head. Kind of between normal and a headache, which is weird because I haven't had a headache in several months. I am not prone to them.
I used to take medicine (pepto-bismol), but it didn't help. Sometimes I would even throw it up. It does not seem to matter what I eat/drink or what I don't eat/drink, nor the time of the day or my location. I usually feel better while I am sitting comfortably, but once I stand up I feel like I am going to be sick. There are times when I will eat in the bathroom, in case I get sick.
The strange thing is that throwing-up makes my nausea go away, so sometimes I make myself throw-up in order to feel better (I am not bulimic).
I was tested for Celiac-disease, but the test was negative. I am going to see my doctor in a few days to see about GERD, then I am going to book an appointment to see a GI specialist.