We mothers feel we have to be constantly doing something with our children to raise them right, I know I felt that way. I would often leave my son with his little floor gym, playing with the hanging toys while I worked for a few minutes. If you get a little break, and he is happy, all the better, you can come back in feeling refreshed and want to play more.
We don't have family where I live, and didn't have many friends when I first had my son (2 and a half now), so we spent a lot of time alone. I did go to play dates at the park, or just took him to the park once he could crawl to hang out with other kids. That way he is around other people, seeing them interact and all that. You can't really create that stimulating environment at home without people, but you can go out once it gets a bit warmer, even just walking around and showing him new things. I remember when my son was two months old and we flew for the first time after he was born. We just sat in some chairs at the airport and he was amazed by all of the people rushing by. He even spotted people above us, that I hadn't noticed. He still sees things we don't, and then after a few minutes of looking around, we find whatever he was talking about.