How about trying to separate out the deep emotional need to have your T respond to your needs and the practical question of changing your days? (I know, I know - easier said than done)

What I'm thinking is if you could see the appointment day just like any other appointments you make in life. If you call to make an appointment for the dentist, your tax preparer, your hair-dresser and they suggest a time slot that doesn't work for you, how do you respond? You probably say, 'that day/time isn't good for me, How about such and such time? And they'll say, "no, we're not available then but we can offer you this other time." And it has much less emotional consequences, understandably so. But still if you could look at it that way, it might ease the tension a bit.

My regular slot with T used to be on Fridays. There were 2 reasons I didn't like Fridays. First of all, the time seemed to crawl between Friday to Friday whereas when I had a mid-week slot, the time seemed to go faster. Go figure.

But, more importantly, now with my Wednesday slot, I am able to ask for an extra session immediately following Wednesday if needed and most times she'll have an opening. She's off Sat/Sun/Mon and Tuesday she's in another city.

So, how I phrased my request was this. "If you get an opening on Wednesday, I'd like to take it. Please put me on the waiting list." So, you might make your request that way. By not asking for a change right now, you won't be faced with an answer that might be too painful for you which is if she didn't have an open slot yet. But if you ask to be put on waiting list, the answer will be YES.

Good luck.