Any antidepressant has as a common side effect a dulling of emotions and sex drive. Doesn't mean you'll get it, just that many do. It's unlikely you suffered permanent damage from such a short term use, but you could suffer all kinds of odd things for awhile after abruptly stopping any of these meds. Again, because of the short duration of use, you should be fine. As for long duration of use, yes, there are many people who suffer protracted withdrawals, which is just a fancy way of saying there might be permanent effects from them. It's not an area that's well studied because there's no profit in finding out these meds can be dangerous and therefore not much research money for such things. We only learn these things over a decade or more of use. These meds were never tested for long-term use, so we're in a black hole there.
I don't think they can cause brain damage. You need to remember there is a reason why you were taking the meds to start with. Maybe the drugs you were taking were not the right meds for you but I think just dropping them all at once is not a good idea. Perhaps you need to make appt. with your p-doc and let them know you are going thru a crisis and if you cannot get in immediately, leave a message for him to call you. Maybe you should start taking the Lexapro only until you get in to see him or try taking 1/2 dosage..but plse. get in and see your doc as soon as you can.