Nausea at bedtime :/

During the day I always have this heavy feeling in my stomach, that's the only way I can really describe it, but it always gets worse whenever I lay down. It's so uncomfortable, and I don't know what to do. Any suggestions on what to do to help this feeling go away, or at least be not as strong? Help please! I wasn't like this with my first pregnancy so I really don't know what to do.