I Am Taking 250 Mg Of Testosterone Once A Week.

I am taking 250 mg of testosterone once a week. I am 58 years old, and in good health. My testosterone levels were on the low / normal range, but I had no sexual desire and was always tired. I am on my 4th week now. I was told to take it for 10 weeks, then go off it for 10 weeks, then repeat. Should I restart the cycle sooner then 10 weeks, being I will loose a lot of my gains, or is 10 weeks right to wait between my next cycle?