Was my starter too warm?

Stop, don't sweat it, you haven't done anything wrong. At 85 F, your starter is going to town in a fast way, especially if you have a hydration level of 100%. Even with a lower hydration, say 70%, the yeast beasts will be working away and eating up their food. However, the starter is still alive. If you keep it at 85F, you'll need to discard a lot of it before you refresh and do that quite often, probably twice a day at least.

Leaving your starter at 60F does it no harm at all. Yes, it will grow slower, taking about twice as long to double after refreshing.

You will find a simple solution in keeping your starter in the fridge, discarding and refreshing every week, maybe every two weeks if you feel lucky, and building up a starter for your loaves on an as needed basis. A firm starter of around 70% is best for this. You won't need to keep a large amount of starter for this method.

In other words, take a small amount of starter from the base starter and then build up to your needed amount for your baking. You'll need to do some planning ahead, a day or so to get it ready, but you'll have the benefit of an active starter ready for work. This will also enable you to vary your starters to suit the type of bread you plan on baking. If you plan on whole wheat, you can adapt your white flour starter to whole wheat in two builds, three builds if you want to be really choosy.

It may not sound free spirited and spontaneous but it's easy. I've done it and so can you.

OK, that's another detail for me to consider.

A slow starter can often be rejuvenated by the addition of some rye flour in the refreshment. I've used organic rye flour from Arrowhead Mills and rye from Hodgson Mills. They both gave a boost  to the activity of my starter and it has been an active starter from the beginning.

If you have doubts about your starter, consider getting some dried starter rather than building one from scratch. If you live in the US, consider that The Friends of Carl starter has been used by members here and all it costs is a self-addressed, postage paid envelope for the starter to be sent to you. You can also check out the New York Bakers website, a TFL advertiser, about the availability of dried starters. I use their "Wagon Train" starter and it works in a Kansas summer and winter. King Arthur Flour also has a starter for sale. It's a useful skill to be able to build your starter from scratch but if you want to bake with a sourdough starter sooner rather than later, you can use these suggested starters without guilt now and still try to build your own.

It's up to you.