Do you live in an area with a lot of colleges? If so, I suspect there are some other kids like your son in your area. Quite by chance, my kids attended a day care that was originally for children of local college professors/employees. While it is not exclusively for the college folks anymore, there are still plenty of them there. Eldest was in a preschool class of 6 kids, and at least 2 were as bright or brighter than her.
While my kids are not PG, and your son's skills are clearly way ahead of the curve (and very likely indicate a gifted kid), I am truly confused by the "Mommy death stares". I read about those on here, but I never got a "death stare" when my eldest was making Duplo towers at 12 months or middle kid was saying, "Clue!", while watching Blue's Clues at 6 months. (Okay, maybe a death stare because I let them watch so much TV.)
Kids at this age don't really play with each other, so it is okay to skimp on the play dates. My kids have not had many play dates. My older two hang out with friends (here, if the house is sort of clean) or elsewhere, but they are at an age where they can arrange (and get there) on their own. My little one keeps asking for more play dates, and while we have done a handful, organized activities are great for socializing. She is camping with the Girl Scouts right now. While he is a little young for stuff like that right now, keep scouts and organized sports in mind. My older two (19 and 17) still play team sports, and while my youngest (10) is not into the team thing, she likes rock climbing and kayaking.
Get some Duplos - my kids liked these at your son's age. Eldest would sort by size and color and then build towers when she was that age. Don't take this as a sign that he is a future engineer - my eldest is clearly a humanities kid. When he is old enough to handle Legos, get some of these. While we have some sets, I purchased a few bulk lots of random used Legos. My kids build all sorts of stuff with their 40lbs of random Legos.
Just go with the flow - let your kiddo explore a lot of things even if you aren't really into all of them. Ours have explored various academic stuff, plenty of sports (we like these), music, theater(ugh, not my favorite but DH has a theater minor), etc.
I have found that I get all worked up about the issue of the moment, then find later that it wasn't worth getting so worked up about. Sometimes these issues are academic, sometimes they are something else, but in the end, the issue wasn't going to cause long term damage to the kiddos. Good luck - try to relax and enjoy your son.
