Ummm who is this??? But I completely understand everything and go through the same thing, especially with having to socialize with people. Whenever you overthink something stop yourself right away. Overthinking honestly ruins you and only carefully think about things that actually need careful thinking. Just calm your thoughts and quit worrying about such little things that don't even matter because thats when the overthinking happens. Also quit being so hard on yourself about socializing. It's stressful sometimes, but stop worrying so much about what to say. It's okay if you don't know what to talk about, everyone goes through this. When talking to others relax. If you don't know what to say begin asking the other person about their interests. Just relax and quit worrying. You will be fine and are not alone:)) And here is a helpful link
http://m.wikihow.com/Start-a-Conversation-When-You-Have-Nothing-to-Talk-AboutView more