I forgot to take my birth control.. and that same day I had unprotected sex, is there a high chance I can be pregnant?

Yes, there is ALWAYS a chance of pregnancy when you engage in sexual intercourse, whether you are on birth control or not.

Not a high chance, but as Curlyben said, pregnancy will always be a possibility.

Anytime you miss a pill, it increases your chances,

Also even when taking them perfectly, there is also still a chance