Eating Troubles

Solid foods are going terrific. Night time feedings are now going poorly. I thought the theory was once the babies start solid foods they start sleeping longer. Our baby is doing the opposite. We've gone from getting used to 6-7 hours in between bottles to now going 3-5 hours if we're lucky. I don't understand it. We made the mistake of eating a ton of solid foods and then suffered the consequences the next day. Actually, the daycare had to suffer from it. In any case, I really don't know what to do to make her sleep better and longer. She'll eat and then go right to bed so I know she doesn't just get up to get up. Any suggestions are welcome.