buying a house?

i am in the middle of buying a house and told my solicitor three weeks ago that i wanted to complete on friday 4th August and he said that wouldn't be a problem. Yesterday he told me that they haven't exchanged contracts yet but all the paperwork is ready. do you think we could still complete on friday?? my solicitor is being vague and i have everything booked for moving on saturday, what do you think i should do?