The back of my wrist thumb side hurts... help

Not sure if it's tendonitis or whatever the medical term is, any of you mommies experience the same? Both the back of my wrists thumb side hurt especially when I grab, twist or apply pressure on it. Before, I only had it on my left hand but now I have it in both. I'm pretty sure it's related to carrying my baby (she's almost 4months old now). From time to time I apply hot compress and massage it, but I'm afraid it's getting worse. Any of you have it as well? I googled it and some do and they call it "mother's thumb". Any other suggestion how to relieve pain or cure it??? Not carrying baby is definitely not an option as I don't have a helper. TIA...