I had quite a dip in first tri, and then it stabilised again. I just kept feeding through, and it worked ok. Feeding to sleep also stopped here during pregnancy (and it was the only way i had ever got DD to sleep other than the car). After awhile, i began giving dd a drink of cow milk at night and then a breastfeed. It helped get her to sleep without having marathon sessions that were doing my head in. I was pretty conservative in offering this, and i think it was around 100ml max because i didn't want her to wean, but it is an option.