Where in the uk are you?
First off - you need long cane training.
Your local authority is obligated to provide it however there’s often a waiting list and you need it now.
Your local authority can outsource it to a provider such as Guide Dogs Association who do this as they have fully trained and funded mobility instructors and it’s a source of revenue for them. Other charities also donir. It should be free to you.
That’s the first step.
The school run with a long cane is totally doable.
I am registered blind and I do it twice a day with either my cane or guide dog - I find it relatively stress free. I started using a cane when my daughter was 2yrs old and my guide dog when she was three. They are life savers.
Also, go into the school or nursery and ask for an appointment with the head. Ask for a care plan to be written up for you so that staff have a guideline o. How best to support you.
Tho gs you might want to put in it include
They locate your child, coat and bag and hand them over directly to you in person
They email any letters Home to you,
They inform you of any signage that may be up on walls that you may miss.

Ask your local authority for a full care plan that undertakes every aspect of your life. It should be carried out by a social worker with knowledge of sensory disabilities.
You need support with daily living tasks, personal care and social inclusion.
By personal care I mean knowing that clothes are clean and matching, no toothpaste on tops etc, not actually getting washed and dressed.
They can provided a PA in your care plan to assist you for a few hours a week - and maybe a cleaner to help you with household chores.
Apply for PIP if you haven’t already.
If you aren’t working you need enhanced ESA.

I promise you it is all doable and you will find solutions.
Yes it’s totally overwhelming and devastating right now but taking some of these steps will get you going in the right direction.
It’s all daunting so I definitely recommend contacting charities such as RNIB, Action for Blind People, Henshaw, Galloway or whoever is your local organisation, and also the Citizens Advice Bureau to help you with all the logistics of getting support put in place,
You are not alone, and you will be ok.
Sending you a Reddit hug from one visually impaired parent to another

In the UK the Royal National Institute of the Blind is the primary low vision charity, Vision Support is another. You'll want to treat your vision and your health separately, the hospital probably won't be able to help you live a more accessible life. Be adamant with your doctors about getting answers and running tests, you may need genetic testing and various scans to find the problem. Outside of that, you'll need training and assistance to make your life easier. A cane or guide dog would make navigating easier, the first step would be visiting RNIB or calling them to arrange a meeting.

just a quick Google search but I think these people would be a good start. Have you hear of the Royal National Institute of Blind People or RNIB?

Please talk to your doctor about LHON. Leber Hereditary Optic Neuropathy. My son was diagnosed very recently. It took ten months to get the diagnosis. He went through a lot, including some of the things you mentioned before seeing a genetic specialist, who took a blood test. Especially if there is anyone you know of on your mother's side of the family who has ever had vision loss. He started with sudden painless loss of vision in one eye, shortly followed by the next eye.

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