I went to Walmart to get doggy diapers. It got the smallest one they had xs. They are too big for her

I have been on vacation for 2 wks. Start back to work tomorrow. How long will she be in heat to where the boys are interested any more. I don't want to separate them. They will tear the house down and I don't want to keep her in a crate all day. I just hope all goes well.