How do I become a professional tennis player?

I'm currently 19 years old and I played first singles throughout my high school career. I chose to give up tennis for basketball but recently I've been thinking about starting up tennis again. According to the USTA rankings I would be a 5.0 or 5.5. I have a really good first serve and second serve, a strong forehand and good slice backhand. My backhand could use a little work but I'm a little rusty right now. Also, I feel like I should work on my footwork and reaction time. Any suggestions on how I can get started on trying to become a pro tennis player?