Parents of high needs children - can you help me be more tolerant of mine?

[notmuchofaclue]

Dd is 2.9 and has always been a sensitive girl. The problem is that she and I are totally different personalities and I'm not remotely sensitive to new environments etc. As a result I really struggle to be tolerant of her or understand her behaviour. I know this is my problem not hers but I don't know how to change it and it really gets me down.
The thing I find hardest is that we can never predict how she'll react when we go out anywhere. If she's not happy (and it's rarely obvious why, in spite of her being a really good talker she either can't or won't verbalise it) she will whinge and shout until someone (usually me) gets fed up and we all have to turn around and go home. Of course, she will also then shout and whinge that she doesn't want to go home. Other times I'll be nervous that she'll be a nightmare, and she'll end up being fine and having a great time. It's just impossible to know but I find it so stressful as she's often the only one being a grump while all the other kids are having a great time. It's as much the feeling that she's missing out on so much that gets me down, as my shameful embarrassment at how she reacts in situations (and of course my own negative reaction to it which does not show off my great parenting skills!).
She can be such a great girl, bright funny and smiley - but i don't know how to bring that side of her out more, and to be more tolerant of the behaviour I just don't understand. It's like I just see red when she starts up when we're out, I don't shout at her but I can feel my blood start to boil. Today we went to a lovely place with a playground and woodland walks, the sun was shining and it was lovely. Within minutes she'd started whinging/shouting about stuff that didn't make sense - 'mummy don't stand there', 'daddy stop doing that' (daddy not doing anything), 'daddy pick me up', 'daddy put me down noooo pick me up!'. 20 minutes of shouting later and we were back in the car, me on the verge of tears and her asking why we were going home.
Please can anyone with sensitive children help me know how to deal with this? It's impossible to avoid situations that will make her react like that because there's no consistency to it. We don't go to soft plays or swimming pools as that's mostly (but not always!) going to get a bad reaction but other than that I am clueless, we can't just lock ourselves away at home.
Sorry that was long, but if anyone has any advice I would be really grateful for it!

Okay two little ideas.

First, is it just the activity that is causing the issues, or could it have started a long time before. So for example: taking too long to put on socks can lead to a meltdown at the playground 5 hours later? The only way to know is to try to keep a diary/notebook. Noting things which go wrong, cause a little stress etc. My 11 year old can't really express her feelings very well, and struggles to understand/tell me why she gets upset; a 2/3 year old has no chance.

Second, it can be a huge relief to just accept she won't be "like other children". Accepting that she finds situations hard, is "slow to warm up".

Finally Raising your Spirited Child might help. If you do suspect ASD may be part of the mix, then do go to your GP and request a referral, you can always cancel if you become totally referred before your appointment comes through.