hello GOG guys! I'm trying to change my e-mail address and for some reason the password on my account is not the right one. Looks like it is too long to be my password. I am trying to change my e-mail because my old one was Yahoo which of course is hacked now. I need a way to put my new G-mail on here but the password is wrong on my account and I can't receive an e-mail message of course.

Contact the GOG support is yout best bet.
GOG staff do not read forum regularly.

If you haven't already, contact GOG Support, as you can't rely on GOG staff reading the forum, especially on a Sunday, and act on your post alone.

I doubt your password is too long. It sounds more like GOG is asking for the two-step login security code. With two-step login enabled (default since a couple of months), your identity will be verified through your email address whenever you log in from a new device, browser and/or location or when you want to change the email address. GOG sends a 4-digit code to your e-mail address to confirm the change/login. Since you probably aren't able to receive these mails, your only chance is to contact support and explain the situation. They will identify you by other means, e.g. last billing details, and help you reset the e-mail address.