The estrogen sides are too much for you because you haven't controlled them. You weren't taking an AI at all until about 2 days ago.
This will pass, but letrozole is probably the best thing for you to reverse a flair up like what you're experiencing, but honestly you'll probably be fine after letting the adex do it's job for a couple more days. Keep taking 1MG EOD until sides go away then adjust from there. Up to you on whether or not you want to quit the cycle now, but you have a couple days to decide before your next pin to see if the adex is helping.
If you don't have any letro, you could also use some clomid or nolva right now to help sides go away faster. I'm assuming you have one of these on hand already for PCT. Note they will NOT reverse gyno but they can help prevent it from progressing while your estrogen is still high...
If you do quit, yes you still need a PCT, and should keep running adex, tapering down until you start.