Dear K.:
Congrats on the new baby boy!
I struggled with BF my third also. My Ped nurse stated it can be tough for the first few weeks with #3 b/c it is stressful balancing all three.
Can someone come (playdate, sis, mom's helper, grandparents) to entertain the other two while you rest and concentrate on just feeding #3?
It is an adjustment. Hang in there, contact the lactation consultants from the hospital ASAP or follow up on the other recommendations.
The LC at Silver Cross were good. Sorry I don't know the names, but they did follow up calls after I was d/c to check on me. Good luck!