You're suffering a great deal. You need and deserve help. And it would definitely be ok to call and ask for an earlier session. Nothing unusual or scary (for the T) about that.

It might not be possible for you to get an earlier session, of course, and you're right, it's really really tough to stuff those thoughts back into the box. Writing them down can help. For me, getting the thoughts onto paper (or a password protected document on my computer) can help me tell those thoughts to stay away for a while, until I am in a place where I can deal with them.

I hope you'll get the help you need.

And welcome to the forum! I'm glad you decided to post here.