Shoplifting, Larceny, Robbery, Theft help someone

[thejrol]

I rented a car from a large rental car company who I frequently do business with. I was pulled over by local police for grand theft auto even though I had the rental contract and all paperwork. As soon as Im pulled over Im yanked out of the car placed in handcuffs and the officer proceeds to search the vehicle. He finds a firearm and drugs in the trunk. After I bond out I contact the rental car company who states it was reported erroneously. The grand theft auto charged is dropped as well as the drug charges on the state level but then the feds arrest me because Im a convicted felon in poss of a firearm. Is this an illegal search and seizure based on the grand theft auto was not stolen and dropped and that I never consented for the police to search the car at all? Please help it would be greatly appreciated. Also could I sue the rental company for all of this madness? ps this is a florida case in hillsborough county that has moved to the middle district of florida-Federal