I would suggest you have a CBC done to see where your potassium level is. Low levels and high levels can be dangerous not only to you but to the baby, it plays a very important role in heart function, muscle and nerve cell function and kidney fuction. (The heart is the biggest thing, bcuz real low and high levels could cause heart to fail)
Most fruits and vegetables contain potassium.
Again, im not sure if your levels are high or low or you just want general information, but b4 putting your self on something, have you levels checked.
If you already eat a healthy diet and increase your intake(for preggo woman) you should not have to worry about your potassium level.
Im not sure bit if you eat a bannana everyday or a few times a week you should be fine. My potassium is low when i went to a checkup a few weeks ago. (16 weeks) So he said get bannanas weekly or everyday and you'll be fine. Its ok to miss a few days.