Chill out!
At least wait for the winter sale. Then buy more games!
Remember that having more games does not mean you’ll be having more fun. Every game you buy, you should be intending on spending at least 10 hours in it, otherwise it may not be worth buying.
The problem went away, so it’s no big deal now.
But if you need to know if it was the fuel or not, bring your car down to low fuel, and add 1/4 tank of fuel from the old company you used.
Monitor how the car behaves until you’re low fuel again. If you have any issues, immediately fill your gas tank with high quality fuel.
Bad gas can cause issues if the octane rating is lower than what it should be, and could cause detonation. If you add premium (93 or 91), you can counteract the really low octane bad gas with high quality gas, and it should prevent damage.