Weaning off the breast - bad trapped wind and constipation

[captainj1]

My DD has always had a bottle of ready made aptimil a day, the rest breast. I'm trying to wean her off the breast as I go back to work in 6 weeks but the more formula she has (all ready made) the more unsettled she is becoming. Her tummy is really hard and painful, bowel movements few and far between and when they come they stink, are dark green and like slimy gravy. Anyone got any similar experiences? She was up every 2 hours last night and the only think that would settle her was breastfeeding, when she would get a few trumps out while on the boob. It just means I'm feeding all night instead of all day...