Toddler has anxiety?

My son is almost 3 years old.

Lately, he’s started screaming and panicking over some random things:

1. In the drive thru when someone is talking to us through the window. He starts screaming and asking me to hold his hand.

2. Whenever I get out of the car/out of sight. We went to the gas station and I had to pump gas & when I got back in the car, he was bawling his eyes out asking me to hold him.

3. Whenever I close a door to a room he’s not in with me (bedroom, bathroom, etc)

He does NOT cry when I leave him at grandma’s or with his dad while I go to the store. He’s totally fine.

He’s just suddenly very clingy during random moments and idk what to do about it.

Anyone else experience this or have advice about this?

Thank you!