Car is overheating but not leaking anything

What is your question?

When I start my car check engine light is on and nothing seems to wrong seems to run fine then about a week ago I noticed my temperature symbol came up and it didn't start to worry me till it was blinking red usually when I first start it the blue temperature symbol stays on till I drive a couple miles and goes off it's not going off and my car isn't leaking any fluids from the radiator?

What makes this problem better or worse?

Nothing that iv seemed to notice

How long has your 1998 Volkswagen Beetle had this problem?

A week