Bleigh

Help or advice to fix my Scion. My car was running fine. Just changed my brakes . I pulled out of the driveway and my tC hesitated to accelerate and then noticed my rpms at 3500. I let off the gas and rpm went down but continued to go up and down as I turned back around.
I did cut the A/C on at first. I cut it off to see if the hesitation would go away but it didn't. I did have someone add a can of freon to my A/C about 2 weeks ago. It's not blowing super cold now after all this. I also noticed that I didn't drive it but 10 miles and it used a quarter tank of gas.
I have a car guy but I would like to know what I'm getting into before I try to get it fixed. Does anyone have any advice or help with my 05 Scion tC issues?

Or help me pin point what could be the cause of the problem?

Please and thank you.