Minimum amount to eat

I had my op at 5.Aug. 2014 , every thing till now is still within expected and no worry from serious complications. My main problem that sone i start eating some simi sold ( this week) i find that i can not eat more than 2 small spoons and start having this annoying epigastric pain. It is not sever pain , just mild or moderate one but i can not eat any more . I wait for about hour and try to continue eating but it is the same. So i returned to fluid intake again. And i have really worry about the futur. Yes i am loosing weight but i am not having a normal life. Can anyone , tell me if this is also within normal or not. Does it will be better with time. I hate being in pain. And what is the normal accepted amount of food i will be able to eat , less then 50 gram is not sufficient to maintain normal life and i do not want to be for the rest of my life on fluids and shakes :-(