Raspy weak voice

Since surgery in May I have has a raspy voice. It makes my voice low and weak. If I have not eaten or drank water in a while it gets weaker and people close to me will ask when is the last time you ate or drank something? I still get tired at times especially when I drop like 6 pounds or so at once. But mostly the voice bothers me. Has any one else had this trouble? I notice some times I speak and people can't hear me and I can not raise my voice and other times it seems ok? Marylou