As others say it depends how your anxiety manifests itself.
Say you're going on a family trip tomorrow.
Totally normal- to check the weather, look up the place online and see if they have a cafe, playground, toilet, look in the cupboards to see if you have stuff for a packed lunch. Check your bag has nappies, change of clothes.
Not normal- lying awake at night because you are thinking about what could go wrong. Not being able to eat properly and relax the night before.
I think that the "totally normal" person is used to the mental load of going out and probably has had "disasters" in the past so is planning ahead.
The "not normal" person should talk to their GP as their anxiety is sky high.
You sound totally normal imo. Sometimes I wish I could turn back time and spend time with the kids when they were younger but I wouldn't pick age 2.
Your h is cheating if he has his sister's help when you go out. If he had say a week on his own, he'd appreciate how much mental energy it takes looking after 2 year olds. Even a trip to the supermarket (where he has to buy say 3 days worth of food that he planned for) is hard and time consuming.
You sound like you're doing a great job with your twins. I found one at a time hard enough!