Dealing with anxiety regarding work?

Hey everyone, I am new to the OCD forum.

So, I work as a nanny and I have to pick two children up when they get out of school, and for the first school I go to I need to be there exactly at 2:55 pm, and then go right to the other school and pick the other child up by 3:20 pm.

I usually leave by 2:30, but lately I have started getting really paranoid around 1:30 and on, and worry that I should have left already and that I am going to be late. I have to keep checking the clock to make sure it is actually 1:45 or whatever, and not 2:45. It is making it really difficult to function the last hour before I have to leave for work, because I am very anxious.

Also, lately on some days one child has been home or at daycare, so I just need to go to one school. This is even worse, the whole way to the school I am very anxious, worrying that maybe I am on my way to pick up the wrong child or maybe I read the parent's message wrong, and I need to pick up both of them. I have to constantly recheck my phone or email to make sure I read it right.

Does anyone have any advice on how to deal with this?