I am feeling very guilty.
I have 3 dds, youngest is 11 and has just been diagnosed with high functioning autism. It is early days and we are in the process of working out how to deal with this and the best places to go for support. I've been a bit anxious about it understandably although the diagnosis is a relief in some ways as it explains a lot of dd's behaviours over the years.
For background - my own mother was a single parent, couldn't cope with me, shouted and ranted at me a lot. There were a couple of times when I was a child that she was so angry with me, she left me in a public place and drove off
She came back again after 20 minutes or so.
I always said I resolved to be a better parent than her and so far I think I am doing ok. I have great relationships with my older (teen) dds and usually also with dd3 even though her behaviour is challenging at times.
Anyway - about 2 weeks ago, I took dd3 to do the bus route to her new secondary school. We got the bus to school, then I took her for a Five Guys burger (her choice) before doing the return route from school to home. On the way back to the bus stop, she started to nag me for various stuff - she wants new trainers, she 'needs' flip flops (not just any flip flops, the Haviana ones), can she have this, can she have that. My responses were a mixture of I'll think about it and saying no to the expensive stuff. But it wasn't enough for her and she kept ON AND ON. Eventually I just lost it and I stormed off ahead of her
I shouted at her and told her to find her own way home, which was a stupid thing to say because at that point she had no idea where the bus stop was. She started apologising but I found it really hard to calm down. At one point, I went round the corner and she lost sight of me. After 10 minutes or so, I calmed down, I apologised and we went off to the bus stop together.
I KNOW I completely over-reacted and 2 weeks on I still feel bad. What upsets me the most is that when she lost sight of me she must have been scared and that breaks my heart and terrifies me that I acted like my mother 
I thought I was a patient parent but the autism has knocked that on its head. Parents of autistic children - I admire you - where do you get the patience?? Dd can't make the simplest decision without a trial, she has sensory issues, can't bear people eating and so on. I am trying so hard to understand how hard it is for her but selfishly, I'm also aware how bloody difficult it is for the rest of the family.