re: "How much money i will get?"
At this point, you will earn a net total of $0.00.
Because you refunded everything. You arleady know this.
At this point, you have two choices:
a) Just accept the fact that you won't get paid. Learn from your mistake and move on.
b) Contact the client and BRIEFLY explain your mistake, and ask her to send you the payment again using Upwork's pay bonus tool. One message only. Graciously accept the result whether she says yes, says no, or ignores you. It is her choice.
You may write to your client:
Thank you again for the opportunity to work on your project. It was a great experience for me as I start out on Upwork. This is embarrassing to admit, but I'm so new I did not know what the Refund button would do, and I accidentally refunded the complete payment of $50.00. If you could use Upwork's Pay Bonus tool to re-send that payment (or any amount you feel is appropriate), then I would be very grateful. Reardless of your decision, thank you for your time and patience."