Im a mom of a 1 yr 8 mos. old baby boy. You have a lot of options:

1. You can invite ur sisters/parents to visit Doha & take care of ur son for even 6 mos. (at least in ur behalf)
2. You can hire a nanny to take care of ur son instead of sending him at daycare center everyday.
3. Set aside ur career goal & concentrate ur career new career as a "mother"

Back in my Phils, Option 1 was good for me. My sister takes care of my son (since birth to 1 yr 5 mos. old).
Now in Qatar, I take option 2. My son is just at home i just check my son (thru phone)from time to time re: meal time sked & taking of medicines & etc. Like you I also go home at 4:30 pm. Just make sure you'll have a caring Nanny. :-)