I suggest you refer to the following links, which also includes other links for additional details.
Pay particular attention to who controls what work is performed, when it must be done, where it must be done.
Check your W-2, box 13 to see if this box is checked.
https://www.irs.gov/businesses/small-businesses-self-employed/statutory-employees
https://www.irs.gov/pub/irs-pdf/p1779.pdf
