Anastrozole is a competitive drug to T, so needs to balance to T levels. That is impossible with weekly injections as T changes too much. Try to get those syringes. You can inject with #29, 1/2"-12mm, 0.5ml [50iu] insulin syringes and inject twice a week, SC or IM.
If you inject twice a week, try to do labs half way between injections always so changes to lab results are not artifacts from changed lab timing.
See stickies found here: About the T Replacement Category - #2 by KSman