You need some routine. My day with my three year old when she wasn't in preschool was something like this:
7 - Wake/Breakfast
8 - Bath/Dress/Start laundry and pickpup room
9 - Play/Go out/Chores
10 - Snack
12 - Lunch?Reading
2 - Nap
4 - Snack/Movie//Play/Make dinner
6 - Dinner
7 - Bedtime routine
Of course that would vary some - for instance , we do the bath at night a lot. My daughter proabably watched about an hour of movies each day on average (some days noe, sometimes longer). But I saved that for difficult times liek when I was trying to make dinner. We proabably had an hour or two of solid playtime each day. I tink we would play most in the morning, and ususally spent a lot f time reading before lunch when we (I!!!) got sick of playing. The rest of the time is doing chores, going for walks, shopping, etc.
Here si the stuff we like ot do to break up the day
* library, especially for storytime
* art projects, painting, playdoh
* playground
* playgroups like MOMS Club
* bath playtime can last a long time
* reading - she is almost ready for chapter books
* board games and card games
* pretned anything - picnic, tea party, princesses, store
* puzzels
I am very much not a "princess" mom. I cna't stand playing princess, although I certainly indulge her frequently. I personally prefer to read, do art, build with legos, and play games.
You can't expect a three year old to go off and play for an hour by herself in another room. You need ot go with her and engage her in the playroom. Or you need to get her a tub/basket and encourage her to pick out a few toys or activities to bring to the main part of the house. Kids that age love to play pretned, dress-up, and are starting to be able to do simple games like Go Fish or Candyland.
It is also a great age for her to help you. Turn off the TV and have her help with laundry, mopping, dusting, vacuming, whatever. And I think food prep is great. Don't just have her make cookies and sweets though, have her make salads or scrub potatos and put them away for dinner.
Every mom has bad days, especially when pregnant with another one, days that seem to never end!!! But I really encourage you to be her guide to finding some fun activities, get out of the house even in the cold, and enjoy your time alone with her. It will give her some wonderful memories of just her and Mommy before the baby arrives.