Should I make an API for users and an API for admins?
You should only have one endpoint, not one for each type of user. What if you have moderators? Will you also create a /mods/login ?
What each user should and shouldn't have access to should be sorted out with permissions.
I'm having a little trouble figuring out if I should have an API for admins and for users splitted. So:
Admins should login using /admin/login with a POST request, and users just /login.
Admins should access/edit/etc resources on /admin/resourceName and users just /resourceName.