Reyna is my first little puppy ever!

So I really don't know a whole lot about dogs...she is now 7 months old and should be starting her period (do we call it that for dogs too? hehe) soon. She is 2.8 lbs. and I was wondering how much these little ones bleed? How long does it last? Are there really little pad/diaper things?...do they work? Any advise would be great...just trying to be prepared. Thank you!!