Hi. I'm absolutely defeated and don't know where else to turn.

2011 jeep patriot. Drove \~145,000 miles til my transmission shat out. Just recently got it replaced with a used transmission, cost about $1400 with labor and whatnot. Was running totally fine.

Last week my battery went, fine, whatever. I got that replaced. Now, when I accelerate I hit about 3k rpms while only going from like 20mph-40mph. When I hit 60mph and my rpms are at 2k it starts jerking and the rpms jump up. Its very annoying considering my commute to school includes highway use, everyone is pissed at me on the highway bc I'm going 55 to avoid the jerking. Its very specific as well: it seems to be exactly at/around 60mph and 2k rpms that it does this, so i drive tenderly and try to keep the rpms just under 2 and go around 55 if I can.

I took her to my mechanic today, he topped off the transmission fluid, took it for a test ride and said basically, "Welp, didn't do it for me when I took it, but if it gets worse or breaks down I'll tow it and use the warranty for the transmission and you'll just have to pay a bit for labor"

which in normal cases would be fine, but I'm totally broke after replacing the transmission and battery, I'm in nursing school and work 1 day/week, supposed to graduate in like 3 weeks. I'm already terrified of cars at baseline and when my car isn't acting right I tend to panic. Is it safe? Do I just keep driving it? I'm at a total loss of what to do. TYIA. 😭