rofl!!! I think I might have the female version of your son! My youngest daughter (to be 4 in Nov) chatters....constantly!! She asks me the same question over and over. When I say we're going somewhere, she expects us to go right then. My other two children were nothing like this! She's nosey, whiney(which really annoys me), demanding, sweet, loving, and even challenging. I get the same feeling of guilt after being overwhelmed by this girl.
I love her with all of my heart. She does her best to annoy her brother and sister. She likes to be clingy at times. She has a wonderful pity act when she doesn't get what she wants. (LOL) In short, she is a normal 3 year-old. She would rather be in my room watching what I'm doing than in her room playing with her toys.
About the ADHD/ADD....don't worry about it. He's too young. You just have to direct all of that energy into a constructive avenue. THIS is the real challenge!! My daughter is now into coloring. She wants to go to daycare (her school). Have you thought about a play group or something along those lines? Give your son someone to talk to...give yourself a little break.
If you are working from home, your husband is at home, and your son is at home...when do you get breathing room from each other? Anyone would start feeling a little crazed without a break. I think that's why I'm glad my kids are going to school and daycare. I get some time to be an adult...even if it's just for a couple of hours. It's not that I don't love them and enjoy being around them...sometimes you just need a little breathing room.
PLEASE DO NOT PUT YOUR CHILD ON DRUGS FOR ADD/ADHD!!!!! Look for other options. When he starts school, do not worry if he doesn't settle down! Don't let the school tell you that he needs meds! I'm speaking from personal experience. My son has had adverse reactions due to ADD meds.
When you get to feeling crazed...step outside and breathe. Take a one or two minute break until you are ready to deal with his energy. Keep a journal of his exploits to give to him later. For when he has children....he'll need to know how to deal with the same energy. LOL
Good Luck and may you have much laughter,
K. L.