Is Pain In The Upper Abdomen Along With Constipation And Diarrhea A Serious Issue?

For over a year I have had pain in my mid-left back that spread to my left upper abdomen, just under my ribcage/heart. For about 4 months now I have also been having alternating constipation and diarrhea with a very foul smell (the diarrhea is only once or twice a day before I get constipated again for several days). Since then I have also been getting nauseas on and off and have a decreased appetite most of the time, but no vomiting. I have lost almost 10 pounds in the last 3 weeks. I feel very fatigued, and my pain is only getting worse. It is usually a deep cramping, but at times it gets so sharp that it s hard to breathe until it subsides after a few moments. I went to the ER and they referred me to a gastro, she recommended an endoscopy but I can t afford it. Does this sound like something serious? If it s just IBS I don t want to ask family for money to get tests done, but if it could be serious I need to find help to pay for the testing.