Be happy and accept this blessing. I am 35 and we're expecting our 5th - definitely a surprise. But I want to enjoy every minute. The Lord is good and he will provide. Keep the faith that everything will turn out great.
I just read the other day an article with a mom of 4. When she was pregnant with #3 she was worried about the financial impact of her new baby. Then she said having a 3rd was not as expensive as she thought, as she had lots of hand me downs from her older kids. You pretty much have already everything you need for a newborn. You may think as this baby was not planned but it was. Maybe not by you but that baby has a purpose in this world. I bet once it's here your worries will go away.
I am pregnant with #3 as well. This one was not planned either. I will be 40 two months after baby's due date. I can relate with you about the mixed emotions. But my worries are more about my own health and wanting to be around for my kids as long as I can be. I worried about being able to provide for all of my kids over and above what they actually need. I don't really worry about the cost of a third child because my husband has a good job. He probably isn't happy about it because it means he doesn't get as much "play" money. For his hobbies. I keep telling myself that God is in control and only he knows what our future holds. I'm just counting my blessings and staying positive. Life is a roller coaster. We found out Monday that it's a boy. I'm so excited about another boy!
This is our third baby in 4 years. This little one was not planned either. I was very upset in the beginning because I was so sick and my other 2 kids are still so young. But now that I'm in my 3rd trimester, I feel much more confident. My kids are ready to meet their new sibling as well. My husband is even happy now! As far as finances, we're going to have to have a little faith that everything will work out in time. Oh, and hubby is getting the "snip-snip" 2 weeks after baby is born. No more SURPRISE babies for this little family!
Keep in mind that there are lots of community and government resources to help families make ends meet.