What do you think??

Ok my mom has never been wrong in telling what a pregnant girl is having.She has gotten every gender right.With me though this is my second pregnancy but the first one ened in miscarriage.She thought I was going to have a boy then.With this one she say's that I'm going to have a girl.Now she keeps saying she's feeling a little boy also.She doesn't know If its from the last pregnancy or if I could be having twins.My fiance said he can have twins so I'm a little nervous.I wouldn't mind twins but I want to know.We have had a sonogram and everything but there was one baby and we look twice 2 diffrent weeks and all week can see is its back.I know that they can miss a second baby sometimes so I think they might be missing one.Another thing is that they say if your having twins you have an increase in nausea.I have been throwing up non-stop all day everyday.Does anyone think I maybe having twins too?