Hi, I'm a kind of a newbie too, so I empathize with your plight. You've found a really great supportive community here. Treat these people with respect and they will happily help you out. I've certainly learned FAR more here than at any other website out there.
In answer to your question...it's kind of a trick question... it's like asking "How much can I make trading stock?" The answer is: It depends.
It depends on your bankroll.
It depends on how much time you have.
It depends on how comfortable you are with risk.
It depends on your skill level.
And it depends on your ability to discern good games from bad ones.
Note, you won't often hear many players talking in dollar amounts...everyone has their own base unit...which is determined by the size of the bankroll and other factors. We're here to learn and trade information, not brag about our wallets. You'll hear someone say, "I won/lost 15 units" That could mean $75 or $15,000...but the point is...it's been standardized into a common phrase for the sake of discretion and simplicity. Teams have won millions. Players have lost fortunes. It's all possible.
"professional play" is a specific term. There was a good post a few weeks back about what it means to be a pro-player.
My advice to you is to study, study, study. Learn your Basic Strategy hard and cold. Then worry about money.
It would be great if someone could talk about the bankroll to unit ratio and how that's determined. I know it's something like your bankroll should be 1,000 times the size of your maximum wager...or something to that effect.
Cheers