So sorry this is happening to you and didn't wanna leave you hanging in the middle of the night.
I've been through very similar my dd is now 20
Honestly I would say move near your family if you think they will genuinely provide support.
Are you working? If so how was that going to be accounted for?
Time to be practical - I know it's hard. Gather up all legal, financial and child related paperwork into a folder.
Check your budget/finances. If you're going to need to claim benefits get that started ASAP as they only backdate to the date you enter the claim not the date of the split.
Whether you think he'll play fair on cm or not I'd advise you also get that claim started ASAP for similar reasons.
Emotionally speak to friends and family honestly and elicit their support. You'll need it.
Sleep when you can, if you're struggling to eat have light/easy things like soup and toast.
If you're really struggling get help from gp
DO NOT tell him anything he absolutely doesn't need to know - he is no longer a friend or ally.
If you have a joint bank account as soon as you can open a new one WITH A DIFFERENT BANK.
Stop paying any bills for "his" stuff
There's loads more that's off the top of my head
You WILL get through this I promise.
Keep your wits about you and be prepared for potential "surprises"
I know you say it came out the blue but there will be a reason and unfortunately sometimes the reason is another woman so try and prepare yourself mentally for that possibility.
Take care of yourself 