First of all,
I too am primary bread earner at the moment. DH is a full-time PHD student, and in another city 3000 miles away
. He can only come back once a month because his intensive research schedule.
We don't have family around to help us either.
Anyhow, I returned to work when DS was 8 weeks. I highly recommend to work part time at the beginning. I did that for two weeks or so and it helps a lot.
Another thing helps me a lot is DS stayed home for the early months when I went back to work. A friend of mine moved in with me to help me. She babysat DS during the day. I didn't have to think about getting DS ready in the morning. At 7 mo, DS went to daycare. At that time, it was such a smooth transition, for both DS and me. Now DS is 10 mo. I still go to the daycare at lunch time, to nurse him and play with him for a while.
If possible, getting your child develop a good sleeping habit. I didn't do well at this. DS was sleeping with me and wanted to be nursed backed to sleep whenever woke up, like every other hour. I always feel sleep deprived. Last month, I finally couldn't stand it anymore. I let DS CIO
: in order for him to sleep better. Now he sleeps in his own crib for the first part of the nigt, for about 4-5 hours, then move to my bed later. It's not ideal but at least I can have a bit better sleep. If your child can sleep good, thus you have a good sleep, then most likely you won't feel too tired at work.
I believe other people will have more suggestions.