Well, I was off T for maybe 5 months last year. I really didn't notice much difference in anything. But then, my libido is the same regardless. I did eventually get a period, but it was around the 5 month mark if I remember correctly. At the least, it was several months without T before it happened.
How long have you been on T and how far apart were you spacing the shots from your usual routine? Not sure if that will make a difference or not.
Anyway, I doubt you have to worry. I think the system takes some time to adjust before it immediately goes back, especially if you've been on it for years.