Body aches with 4 month old baby ,41 yr old momma

I’m breast-feeding my 4 month old baby and caring for my two-year-old toddler. I am extremely achy five days out of seven. I haven’t went back to working out since my 2 year old .I felt OK while breast-feeding my two-year-old up till he was 1 years old , but now with my 4 month old, it’s kicking my butt . Also I’m 41 but like I said, I was perfectly fine with my two year-old, which kind of rule out the age, I could be wrong .

Does anyone have any supplements or recommendations?