im a intellegent, social girl but im really slow on picking up when someones being serious or joking. and its started to get me into all kinds of situations with my friends. is this a medical like syndrome kinda thing or does it just happen? if so what is the medical name for it.

To my knowledge, there is no official name for this difficulty. The closest term would probably be anhedonia, which means the inability to experience pleasure. But that does not sound like you, since you are an outgoing, friendly person. Difficulty seeing humor seems to run in families. If so, then you would not have much early childhood experience in seeing humor. It is probably a learned capacity.
You are not alone. I have known a number of people with that trait. Since it is causing you trouble, here are some ideas to help you recognize humor.
l. If a person says something that sounds serious, but has a smile and a glimmer in their eye, they are joking.
2. If a person says something that seems very odd in that context, they may be joking. Puns, or subtle humor fit this category.
3. If they have a very serious look on their face, then they probably are serious.
4. If everyone else is laughing, then it is a joke. Try to laugh along with them right away, even if you don’t see the joke–assuming you want to fit in with the group. Or, if you want, you can say “I don’t get it,” if they are very close friends, and they will explain it.
5. If your good friends say something out of the blue that sounds insulting, it is probably humor, like what we call “ribbing” someone. Don’t get mad. Just play along with it. To know for sure if its a joke, just say, “Are you joking with me?” Or if you and your friends are familiar with this phrase, you can say “Are you pulling my leg?” Or “Are you trying to yank my chain?”
If you did not see the humor at first, try to figure it out later. Maybe you can develop that capacity. It sure makes social life more fun.
Good luck to you!
aspergers possibly?
adhd.