I am 28 years old

On Wednesday night I woke up with very painful cramps in my upper and lower abdomen. I started vomiting and then eventually got to sleep. The next day the pain was still there but was only in my upper abdomen. I had cereal for breakfast. The pain got worse and started to radiate to my lower abdomen again. I vomited again. Since Thursday I have had constant pain in my upper abdomen and sometimes the pain gets worse at random times. I notice that it gets worse whe I eat something, though I have only eaten tiny amounts due to having no appetite and worry that I will vomit again. I have been opening bowels as normal but the pain seems unaffected by bowel movements. I don't feel constipated or gassy. I cannot book a docs appointment till Monday. Any ideas of what this could be would be appreciated.