I'm seeing a lot of what they call 'splitting' with your T here, which is when, in your mind, she's perfect one minute, and completely useless the next. It's not a very healthy way to build a relationship with anyone like that, yeah? Because none of us are perfect, but that doesn't mean we're completely useless...
And I'm also thinking that you're kind of expecting the impossible from your T. You cancel without notice, but expect a detailed response to your "I'm not showing up today" email - is that reasonable when you're building
any kind of relationship? You didn't show up, so, why would she reward that with "Well, let me give you a whole heap of my time anyway..."?
It was mentioned earlier in the thread that while you've identified an attachment issue, but your approach seems very all or nothing, and I'd agree with that. Your options as you express them seem to be either she becomes the "unconditional love" figure that you want, or you're going to throw in the towel.
You may well get an unconditional-love relationship with someone, but as
@joeylittle said, you have to build the relationship with yourself first. And whilst your T is there to help you with that, and model the behaviours that you would expect in a healthy adult, their relationship with you will always be professional; as your T. A T is not supposed to be a surrogate parent. They don't (or shouldn't) love you. And they don't even accept us unconditionally- for example, if we cancel appointments without notice, that's not really ok. We expect them to show at the agreed time, and actually, that expectation is mutual.
So, a T certainly isn't intended to be the "unconditional love" figure we missed out on in our childhood, not by a long shot. They're our T, they have a very specific job that we pay them to do: help us recover.
If you're feeling too attached, that's really really common. But as with any relationship, it's about recognising issues and dealing with them, not recognising issues and abandoning ship.
There's a lot going on here, but I guess the short of it is that you seem to have a fairly impossible expectation of what your T should be in your life. And if you decide not to turn up for appointments, then it seems pretty rough for her to invest a whole lot in replying to your "I'm not coming" email. If you have something you want to discuss, you do that at an appointment, you don't fail to show for an appointment and assume she's going to switch the rules of engagement to email-appointments instead... Poor lady can't seem to win, you know?