Maybe you could tell us a little bit more about how you scoped those projects and how you handled contracts and payment terms.
It would definitely help if you told us how you sourced those clients. Did you network your way into them, or get them off outsourcing sites?
How big were the clients?
You're not one good client away from all your problems changing; you're several business model changes away from having a sustainable business that will generate fewer abusive relationships, and, over the long term, the luxury of being picky about your clients.