Cuddles just went into her first heat and i'm not sure what to do?!?!

Should I use diapers? she goes on her pee pee pads and she's not bleeding too much and she weighs 4.2 lbs right now. Also on friday i'm getting a new puppy and he's a male and is 11 weeks old so should i keep them apart still or will it be okay since he's so young? i have too many questions to ask but those are the ones im concerned with the most.