I fished my ball out of the loft now that I am 32 wks and feeling heavy - but DISASTER!! The valve has got lost and I can't use the bloody thing. Duct tape is no use (surprise!) and the bike shop I visited looked at me as if I was deranged... any bright ideas?? I lived on it for the last 6 wks of my first pregnancy and I really want to avoid buying a new one.