Post Partum Hair loss?!?!

Jan

I have fine hair to begin with. I had a little boy 5 months ago and the last few weeks my hair is falling out in CLUMPS when I brush it after a shower! it’s so scary when I wash my hair and see that much fall out each time. Is this normal? When does it stop?!!? is there anything I can do? Should I freak out and call a doctor?