You could have a variety of medical conditions. One that comes to mind immediately is intestinal parasites. Worms in your digestive tract. If that is the case you will need medication to get rid of them or they can eat away at you and cause you to become anemic.
Another issue could be obstructed or twisted intestines which could be fatal.
I know you don't want to go to the doctor, but nothing anyone can tell you here will clear your mind or make it go away. Please reconsider.
I had a tumor 2 years ago and had these symptoms as well. It was benign but caused me to become very sick. I felt much better after it was removed.
I'm not telling you these things are definitely wrong with you, but I am showing you how serious it could be.
If you cannot afford a doctor then go to the ER and tell them you need financial assistance and see how they can help you with the bill. You might be surprised at the ease of some of the payment plans allowed and sometimes the bill may be erased altogether based on your income. It's not worth your life to sit around and wait for it to go away.
Your problem sounds serious!