Mine are going to be a lot further apart than yours, but I also struggled with the first half of the pregnancy and neglecting DD--I was throwing up so much though and just felt awful, so there wasn't a lot I could do about it. If she was (and is) happy playing on her own, I think its good for her to develop that skill and to learn to entertain herself. And honestly, now that she is older, she comes up with such amazing insights/games/ideas--I'm so impressed with how her imagination is developing--which I don't think it could as well if I was constantly providing the entertainment.
And since we do have a somewhat lengthy winddown routine for nap and night (1-3 books, prayer, 1-3 songs), I know she is definately getting some quality attention from me each day, not to mention all the outings we go on--even if its just to the stores, that is educating her. I try to take advantage of the things we are already doing to teach her informal lessons, like counting and her alphabet. At 26 months, she knows the abc song, can recongize the letters that start her name, Mama and Dada and points them out to us everywhere we go, counts to 10, and can actually counts objects up to three or four on her own all the time--and this has all just come from singing and talking with her as we go about our day. I hope as she gets older, I can do a little bit more formal teaching with her, but for now, I feel pretty good about the education she is getting just staying at home with me and playing and running errands.
NOw, when I was really sick, I did even less--lots of TV time then, but it only took a week or so of telling her the TV had to rest and was sleeping to get her out of that habit and it doesn't seem like any harm was done, so do what you have to while your exhausted and just hang in there!
~Kim