Lost my Mucus Plug

So I am 37w2d pregnant with twin girls. I am getting induced in 8days. Yesterday I was having contractions 5-7 mins apart all day. So my husband and I decided to go the the hospital at midnight. When we got there and was set up to the monitors the Doc came and checked me. I was 1.5cent and 70% effaced. She checked me three times til 8am and I have not dilated anymore. So they sent me home. Hours later around 7pm I went to go to the bathroom and to take a shower and when I wiped, I noticed I lost my mucus plug. I have a little bit of cramping and I'm still contracting but not as bad at it was yesterday. Has anyone else ever went through this? And how long did it take for you to go into full blown labor?