Apple ID and Subscriptions

I have 2 Apple IDs. The first one is under my gmail address and is where all the content I've purchased over the years resides and is where Apple Services and Subscriptions are billed. The second is under my @me.com address and is associated with all my devices and is where all my iCloud data reside. When I recently extended my AppleCare subscription for my iPhone it was billed to my @me.com account. I could see the amount being charged to my credit card but couldn't see it from Settings-MyName-Subscriptions since that was logged into my Gmail Apple ID so I couldn't cancel the subscription. I finally figured out how to sign out of my Gmail ID and into my @me.com ID to cancel the subscription but I can't reverse the process and get back to my Gmail ID account and therefore can't access any of my content or manage payments and subscriptions associated with the Gmail ID. I'm still logged into the Gmail ID on my iPad and Mac but cannot access anything from my phone. I'm stumped.