So I was trying to get on the freeway to go south. It was raining hard so I must've missed that the lane I was in was a right turn only to go north on the freeway. So I ended up driving straight and when realized I was in the wrong lane it was too late. The car that was in the correct lane honked at me and it kinda shook me up. Should I worry about getting in trouble? Would a cop give me a ticket for that?

It's not like you'll get a ticket after the fact. If a cop did see you go straight in a right turn only lane, yes, you would probably get a ticket. Just be more careful in the future, but don't worry about it now, it's over and done with.

Yes, it is illegal to go straight. If you find yourself in that lane and unable to move over, then you need to make a right turn and then figure out another route to the highway.

Yes it is Illegal look at the Sign Painted on the Street

What's done is done. Be more careful in the future...