Been exactly where you are now - well over 20 years ago. Sorry for the loss.
Way back when I started at first on 4 week or 3 week injections at a doctors office. I did this for the first 5 or more years. It got tiring driving to the doctors, issue with travel. Then I moved to every two weeks and did it myself with 1.5 inch huge needles. You get used to injecting yourself, I know it is difficult to do at first.
I recently (thanks to this site) switched to once a week 100mg T enthate injections and using smaller 5/8 needles. No doctor ever suggested this to me - I had to find out about it here and other sites. I like the smaller needles which take more time to draw, but it is so comfortable to inject.
My targets have been to keep my total T over 500, and ideally over 600. Most doctors are okay with even lower levels - but forget it. I am averaging 670 now and feel very strong. With due respect to KSman, I am not convinced that going to twice a week injections is all that much better than once a week. However, there is clear data that injecting beyond once a week is not good at all. Please forget 3-4 week durations.
I am working on controlling excessive E2 (estrodiol) and currently trying Arimidex. I had tried tamoxifen but not sure it did much for me. I am an over-responder to this Arimdex and my E2 dropped too low. I have settled for the time being on taking 0.25mg once a week at the time of my injection. This trims the slight spike in T conversion to E2 that occurs around day or two of my injection. After this I suspect my E2 is fine, and my T levels do not drop significantly in the one week time frame between injections. I remain open to adjustments in my protocol.
You are facing a life time of supplementation, My suggestion is learn to inject your self weekly. Monitor your T, Free T and E2 levels and watch how you feel.
I hope you are dealing with the emotional aspects of all this. It sucked for me as a young man all those years ago. No lance Armstrong and yellow bracelets and support groups back then for this. So much more available to you - even dating sites for cancer survivors these days.