Control in barrel racing, means you have control at ALL other times you are riding your horse.
Typically, when a horse goes out of control on the pattern, its when the horse has been asked to go too fast too soon.
How long did you walk the pattern? Days? Weeks? Months?
How long did you trot the pattern?
To put this into perspective, my horse I am currently training for barrels was walking/trotting the pattern for over 2 months
before I ever attempted to lope it. It is all about knowing your horse and knowing what they can handle.
Do you have any videos of you and your horse doing the barrels? It's hard to guess what's going on when we can't see it.
Either way, I like my horses to be able to do the following things before you start barrel work:
--walk, trot, and lope on a loose rein, and relaxed
--stop softly and immediately from any speed
--back up freely when asked
--give to the bit in any direction, and break at the poll
--neck rein and direct rein
--be able to sidepass and two-track
--can execute a turn on the fore, or a turn on the haunches
--simple lead changes and flying lead changes
--can perform “perfect circles” with little help from the rider
If you can't do those things first, then you won't have complete control of your horse on the barrels.
I suggest you read through the barrel sticky on this forum. It has a lot of good information in it. Barrel Racing Exercises and Drills.