The lower back and hip pain is from baby pushing on your sciatic nerve, a mucous plug can be different colors, mine was brown and yellow. If it's a pea size you didn't lose your whole plug but it's very possible you lost part of it, it's normal it'll grow back and stay until your body is wanting to have the baby.

my lower back is killing me and my hips hurt. but i am only 28 weeks

i have about a pea size amount i just found

tint*

Snot...thick snot with a reddish grey tent

Google it