D.W.
OK, calm down and relax. There are no decisions to make! Don't even consider what it sounds like you are considering.
Let me start by saying my boys are 17 months apart in age. I got pregnant with #2, when the first one was 9 months old AND my husband didn't (think) he wanted another child. But once you are in it, you deal with it.
My husband worked nights and had to travel every other weekend, so I felt like a single mom most of the time. It is hard the first year. Now my sons are 4 and 2 1/2 and they play together, they learn together and are best friends and it makes it easier to deal with.
Our family is out of state but we have good friends. Some things you could do for help:
-see if family, even extended family like a great aunt, cousin, older niece and come to help you in the 3rd trimester, or after the birth.
-with enough notice, can your husband arrange to be off to help towards the end, or once the baby is born?
-Hire a night nurse, or mothers helper if you can afford it.
-send your 1 yr old to MDO programs a couple of time a week to give yourself a break during the day to rest
-get your son involved with setting up the baby room, getting things ready for the baby. Get him a little bear that is his 'baby' to care for. That will help with bringing a new one.
-lower your self expectations on a clean house, empty laundry basket's and home cooked dinners. Be proud in a 'picked' up house and the fact that everyone has a couple pair of clean underwear..:-)
-it's good you are working out and getting your body back in shape, you can keep that up through your pregnancy and focus on it again once the 2nd baby is here.
You can do this, many women have and it will be a joy and blessing to your family. send me a private message if you want to talk. That might help too, just getting your fears out to an objective person...hang in there.