Sorry to hear of your gastro problems. I have Crohn's (since I was 24 yrs, now a young 63 yrs!), but my late twin brother and elder sister didn't/don't have it, although I understand it does tend to run in families, especially in Ashkenazi Jewish people, who emanated from Eastern Europe, although I am not Jewish, but there is a question mark over my maternal grandfather's ancestry.
I live in England, where luckily we have socialised medicine as in Canada, so don't have to pay for medical services, but it can take a long time to get referred to a specialist, if the problem is not life threatening, so can sympathise with your not having medical insurance. By the way, I am appalled by that situation, the US being probably the richest nation on God's earth. Your politicians can spend mega bucks on war mongering, but why can't they give the basic necessities of life such as health coverage to all their citizens? Beats me.
I am appalled that the doctor you saw did not do any tests? Does he have a magic crystal ball? AArrgh!!
I really don't know what to suggest you do - I have read that County hospitals in the US will see patients who don't have medical insurance, free of charge, but have no experience of your systems, except when I was hospitalised in Florida with a rectal haemorrhage, when on vacation at a friend's home, and I had travel medical insurance.
Perhaps you could ring your local hospital, tell them of your situation and see if they have some kind of programme to help you.The doctor you saw could, possibly, be correct, that you have IBS, but without definitative tests for inflammatory bowel disease (Crohn's and Ulcerative Colitis), he cannot possibly make that judgement.
I am sorry I can't help you further, but if your symptoms persist, please try and get help from another doctor. Plead poverty, whatever, but get seen!
Take care,
Liz.
Oh, and have never smoked, drunk, or done anything like that before