I’m not trying to poo-poo your frustration, but hear me out on this.
You may need to be more patient.
One month is a very short time. My first month I gained less than a quater inch (about 0.2 inches). When you gain this much, you wonder if you REALLY gained at all. You wonder if you just measured wrong the first time. It takes a good half inch gain to really be sure that you’ve gained at all. So, I, too, was wondering if I was really gaining the first month. Now I’m almost into my third month and I’ve gained a little more than half an inch. After doubting whether it was working at all during the first month, I can definitely say with certainty that it is working now (my girth is up too, and it definitely looks beefier).
Consider the following. What if you had actually gained 1/16 of an inch this month, and had just measured wrong the first time. You would not even notice the difference in size. And even assuming that you had indeed measured correctly, it would be difficult to be sure of such a small gain in measurement anyway. You might think that you had only been pressing down harder or something.
But let’s say you did gain 1/16 of an inch. At that rate, in 4 months you would gain 1/4 inch. In 1 year, 3/4 of an inch. In 16 months, 1 inch.
If I were you I’d stay at it for another month and then meaure again. If you’re still not even 1/16 of an inch bigger, then I think you should indeed re-evaluate your methods.
You say that you jelq 30 to 90 minutes. This may be too much. You MAY want to limit yourself to no more than 30 minutes and see if that works better. Also, how often do you do this? Not everyday, I assume? If you are doing this everyday, your lack of rest days may be hindering your progress. You may need more rest days.