Cockney-si, just a couple of thoughts.
Firstly, she dumped you by text (how cowardly is that??!!) and has now cancelled your meeting tonight. She may say she wants to remain friends, but she evidently is looking out for herself first. What kind of a friend is that? The bottom line is that you deserve much better.
Secondly, I know you have to go round to hers to retrieve some of your stuff, but you're kidding yourself if you think you can win her round somehow. When you go round there, would it be possible to take a friend with you, partly to give you moral support, and partly to stop you making an idiot of yourself? (And also it might be handy to have someone help you carry stuff!)
The reason I feel so strongly about this is that some time way back in the last century, before Mr Frog was on the scene, I dumped someone by letter (no texts in the good old days!), and I've felt bad about it ever since. I did that as an easy way out.
So listen up to an old lady who knows what she's talking about!