Was I misclassified as a independent contractor?

I was hired as an independent contractor to work at a large marketing company. I was paid hourly and employed through a temp agency. I never accrued vacation time. It was a 20 hour or so work week. I did special projects but also managed BAU initiatives for over 3 1/2 years. The large company is restructuring and I was let go. I will not receive any severance which does not seem right. Given that I oversaw BAU responsibilities I feel that I should have been brought onboard as a part-time employee. Not sure if I have been taken advantage of in any way and am entitled to any monetary damages. Thanks.