I feel like second-guessing yourself goes hand and hand with social anxiety, it makes you feel like you maybe overshared, talked too much, were awkward, or were weird.
After being with people, you always feel weird, like do they still want to be in my life? It makes you feel almost uncomfortable, don't worry though, a lot of people feel just like you do. There are many instances that you feel this way but so do the people that you are hanging out with. But trust me, you shouldn't feel this way, if your friends or your significant other still want to hang out there is honestly nothing to worry about.
I know it's difficult to not overthink and not second guess everything you said or did but you are who you are.
So what if you tend to ramble on or apologize excessively? Yes, sometimes it can get annoying, but if your friends truly love you and understand who you are then they will get that sometimes you do that. Now, I'm not saying that you should just talk and talk and not let them get a word in edgewise or just constantly apologize when it's really not necessary. I know that sometimes it can happen but try and catch yourself because honestly, it will make you feel anxious and self-conscious in the long run.
Be true to you, you can only be yourself and that's it. Don't try to change yourself so that more people will like you.
In the end, if the social anxiety that you have or the self-conscious behavior becomes too much for some people, then it's okay because it really can be overbearing sometimes. But you will find people that understand your struggles and can help you overcome them. Be the best you that you can be and that's all you really can do. Don't worry about the little stuff so much, it's not worth it.