If it's less than 20000 try KCB Mpesa loan on you safaricom sim menu. See what you can qualify. Then top up the balance with mshwari.
For future Convenience, get a credit card but ensure strict discipline on its use.
Banks will always come to you when you don't need them and dessert you at the hour of need. Credit card with discipline can reduce the pain. Just pay the bill in time
punda amecheka