So many aches and pains

I'm almost 7 weeks postpartum and starting around week 5 I noticed that my joints started to hurt, particularly my fingers, hands, wrists, knees and shoulders. Now I'm also starting to have aches in the muscles in my back and the outside of my calves. It hurts to move and 2 days ago my hands hurt so bad I couldn't open the gallon of milk. I feel like I've been hit by a bus. I wasn't even aching like this after giving birth. Has anyone else had joint pain and muscle aches starting a month after giving birth and know what caused it?