There is a very common phenomenon around the 6 week mark of TRT, where some of the benefits seem to diminish. No one knows why that is, though we believe it is because that is the usual time window where your natural T production shuts down completely after starting TRT.

Despite the fact that chemically speaking the testosterone you inject is exactly the same as the testosterone your body normally produces (after cleaving of the cypionate, enthanate carbon chain), it seems that the body takes some time to get used to an entirely exogenous T supply. It seems to recognize the difference between T you inject and T it produced.

Most men we work with start to regain the initial effects of TRT if they tough it out for another 6 weeks, at which point your body becomes used to the environment of only exogenous T. In a sense, it stops missing the endogenous T, and becomes accustomed to the exogenous T.

The other option would be for you to help your body maintain some endogenous T production. The simplest way to do this is with the addition of hCG (human chorionic gonadotropin). This is a peptide that mimics LH and "tickles the testicles" to produce a little bit of T.

You may also be right about your estrogen being the cause. Your mention of increased anxiety makes this a strong possibility. Estrogen levels above 40 are enough to cause symptoms in men who are sensitive to E. I would recommend waiting until you see your doctor and have lab tests done before adding a new medication.

Basically, all that is to say: if your labs show elevated E, then it might make sense to try anastrozole. If your labs are normal, then it might make sense to try hCG.