Go to Planned Parenthood and get an exam. They charge on a fee scale based on income, if you are low income you will not be charged much or at all. Tell them you're afraid you have a big ovarian cyst or a big fibroid.
Do you have Medicare? Can you maybe see a doctor at your college if you are attending one? It sounds to me like to need an Ultrasound as soon as possible, and need the opinion of an actual physician. Does your abdomen feel rough or liquidy? If it feels rough, it's mostly some kind of mass buildup. 8 months is quite a while, it's better to get treatment now as it will only get worst.
Money can be right but you can always find a way and yor health is most important. Try a college health clinic or Medicare center or a charity hospital. They go off income and you may not have to pay at all. I had the same experience and symptoms as you, I looked 8 months pregnant, abnormal periods with pain, etc. I had a massive ovarian cyst containing 6 liters of fluid. Had it removed surgically yesterday. You need to be seen ASAP because it could be benign but it could also be cancer if it's growing very quickly. Not to scare you but you should be seen. Even if it isn't cancer it sounds like an ovarian cyst and it can severely damage your organs and health. The surgery is not so bad either. Best of luck to you.
I also have back pain but I fell through the roof over a year ago so I've been assuming it's that but it's only in my tailbone region.