I gave my boyfriend over $6000 almost 4 years ago because he was in danger of losing his house. It was assummed he would pay me back when he got some money. I have only received $100 to date and we just broke up. How do I go about getting the rest of my money back?

Did you ever hear what an assumption does - if you have no documents stating he was going to pay you back, no terms written for payment - just your word and your understanding - then he can say it was a gift. It is he said/she said. You can take him to court - not small claims. But you need documentation. Dates, amounts, terms of the loan, witnesses, etc. He did pay you back $100.00 so there is some background knowledge that he did understand he was to pay back.
So you need an attorney. Good luck.

If the $6K is over the limit for small claims court in your area, I would still file for the max allowed in Small Claims court. If you hire an attorney, you will probably have to pay more in attorney fees then the difference.

I agree with Shy, however, without documentation you don't have much of a case. The $100 doesn't show much unless the check says "in payment for x loan".