What Causes Increase In Breast Size And Stomach Pain?

i have been having regular periods but recently my boobs have been getting beigger heavier and painful my belly is getting bigger and harder and i can feel like movement in my belly i have taken at least 10 -15 hpt al neg and even my ovulation tests are wrong i have a 10 month ild daughter and apart from the morning sickness which comes only when i havent eaten i feel pregnant but i dont know what is wrong plaese can you give me some advice xx