Look up the local library story times and see if your local bookstores have a regular story time, too. Make yourself a routine--- Monday is stay at home day to get laundry/housework done, Tuesday is story time at the library, Wednesday is splurge day (spend money by going somewhere that isn't free, no idea what's in your area but an indoor bounce house place like Monkey Joes, or Chuck E Cheese, the zoo, or whatever is local to you), Thursday is bookstore story time, Friday is McDonalds/ChickfilA playland day (go for lunch, or to save money go in between meals and just buy ice cream and/or drinks). Of course that's just a sample schedule, but you get the idea. Keep it flexible in case you get a play date with a friend or it's nice weather and you want to go to a park or whatever. But having something to look forward to each day is amazing for the psyche. I have older kids, too, so my day is different because it involves getting up to get them off to school before my day with my youngest one even starts. But once everyone is off to school/work for the day, it's great to know I have somewhere to go that day to fill up time. I do try to schedule a stay-at-home day once a week so the chores don't get away from me. I am also not strict about needing to be home at a certain time for his nap.
Have you looked into joining a local mommy group? There are so many-- I have no idea how you can even find any in your area other than www.MOMSClub.org, yet I know there are so many local mommy groups. Maybe call the hospital's OB ward and ask if they know of any, ask at your pediatrician's office, ask at the local kids consignment shop, etc