You didn't screw up, the universal coolant is perfectly fine. Don't waste money changing the coolant again. I have used universal extended life coolants ever since around 2006 in vehicles of every make/model/age, over hundreds of thousands of combined miles with absolutely no ill effects at all. This includes 3 different Toyota Corollas, two of them being the same generation as yours. I've done drain/refills and top offs of whatever is in the cooling system with universal coolant, no problems with either case. The universal coolant really does assimilate with whatever is in the system without problems, don't believe the nonsense you'll hear about gelling, etc. Don't waste money on OEM coolant or even the aftermarket Asian formulas, there really is no need. By the way, the universal coolants I'm using are the cheapest ones I can find - house brands like Walmart's Supertech and Napa 1EXT, mixed with tap water no less. No problems at all.