I follow every precaution ordered by my urologist but still have chronic uti's. I've become resistant to the top 3 antibiotics. What's my next step?

Fluids. Drinking more fluids especially water is helpful in preventing or delaying uti's. Safe sexual counseling is also encouraged such as voiding after intercourse. Have a urological work-up to include an imaging study of the kidney such as a kidney ultrasound and a telescope in the bladder to look for obstruction. If all tests are normal, increase your fluid intake and monitor for infections.
Further eval. If you have a multidrug resistant bacteria causing uti's, then you need to be evaluated for underlying problems such as undiagnosed stones, dysfunctional voiding, constipation, urethral stricture or diverticulum, and association with sexual activity. See your urologist for this.