Sounds like the frame is too big for you, but you should still be able to ride ok. A good way to work on your balance is to find an open area (empty parking lot) and ride without worrying about what direction you are going. When you feel like you might fall to one side, turn that direction and that will correct your balance. After a while it will become second nature and you will do it without thinking and the adjustments will be much smaller. That's how I taught my kids to ride and they caught on in a matter of days.
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2018 Breezer Greenway
2011 Raleigh International
'73 World Voyageurs -
Proud owner of all three colors made! Orange, Blue , Yellow .