I was a terrible actor as a teen as well, except when pretending to be emotionless and pretending that nothing bothered me in order to get people to leave me alone. It becomes easier to act as you meet and interact with more diverse people (college provides a good environment for meeting different people). I have found that as I talked to more people on a more personal level, it was easier to understand how others act. It also helped when I stopped caring about being "normal." Funny thing is that you will be (at least I found myself to be) more natural/normal by accepting your quirks and owning them. Just because you may have some "mental disorder," that doesn't mean that you can't just be yourself (as long as your not hurting anyone in the process). Also, I may have been diagnosed with other things along the way, but I reject those diagnoses because they don't help me to improve myself (and thus, they are probably wrong, except one, GAD, which I think is in the right ball park, but not exactly right since my anxiety is only about social things because I can't predict what people will do or how they will react to things I say or do (only towards superiors though), and was only about health things for a couple of years until I had the right medicine to help with my ADHD which stopped the twitching problem and many other problems that made me feel anxious about health). Sorry this paragraph kind of turned into a rant (it is late, and my brain is getting fuzzy...)

I too take things too literally. I still find myself getting fooled by sarcasm from time to time, but I am getting better at detecting it! Since I am female, I can play it off when I accidentally take something seriously that was meant to be a joke without super negative repercussions. It's still embarrassing when it happens though. I've trained myself not to react until observing the reactions of others in a group, then I just mimic their behavior. I've gotten this down to be more natural now, so it is almost an automatic behavior, though that could be bad because I won't remember what the group was talking about due to spacing out.

By the way, it also confuses me as to why they would say that they want to "hug" you because of taking something too seriously. I've never gotten that reaction myself, though I have had people tell me that I was "funny." Maybe it's just a cultural thing from where you are?

Anyway, Good luck on your assessment!