Anyone else come off as "rude"?

I have manners, I always say please and thank you, but I've realized that I come off as very rude due to my social anxiety/awkwardness. People must assume I'm just a boring bitch with a high ego. That's not the case at all. I don't know how to flow naturally in a conversation so I dread talking to people.

My parents had a dinner guest over and I didn't say a single word the entire time because I was so nervous. I finished eating and cleaned up my plate, then went to hide in my room. Currently still hiding. I don't WANT to hide in my room to play video games anymore and I'm tired of ruining my own social life--but I just don't know how to get better. Other girls exclude me in their conversations because I am so painfully awkward. The weird thing is, I'm completely normal in my head. Once I start talking though, my words come out in a jumbled mess.

I know my dad is gonna come scold me for being so inconsiderate once the guest leaves. And yes, I completely understand how rude I must seem. I just don't know how to properly socialize. I wish I could wear a name-tag that says: "I promise I'm not rude, I'm just awkward." Anyone else struggle with this?