A derivative is a work the builds on a work created by someone else, incorporate its elements but adding new elements to the original work. It is often difficult for courts to decide whether a work is "derivative" or "transformative". A transformative work does not infringe copyright in the original work because it makes such major and dramatic changes to the original work as to be considered completely original. Courts have been increasingly willing to give artists the benefit of the doubt where there are reasonable arguments that a work is truly transformative. However, it is not enough that you "do in interpretations in your own style". Rather, your interpretations must be viewed as independent works of art standing on their own merit, rather than building or improving upon the work of others.
The real problem here may not arise from copyright law. Your real problem may arise because celebrities have rights of publicity, and if you attempt to profit by selling drawings that contain their images you may violate rights of publicity without consent of the celebrity. Attempting to profit by associating your art work with famous celebrities is a dangerous business these days and courts are not reluctant to find that art of the type you create violates rights of publicity. It sounds to me that you are a talented artist---why not create original work that stands on its own merit rather than run the risk of expensive and financially disastrous litigation.
"Can i get in trouble?" Define trouble.
Criminal Prosecution? Really unlikely.
Civil suit? Maybe, with increasing probability as you get more famous.
A derivative work applies to copyrighted works, there are a whole host of other legal matters in addition to copyright to worry about.
You should contact a local IP attorney to have a consultation and go through everything.
"A “derivative work” is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a “derivative work”. "
17 USC 101 http://www.law.cornell.edu/uscode/text/17/101
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.