Tough call - the issue is you are on 250-300mg/week now right - trouble is - that's a bodybuilding dose and your Endo is going to freak.
If it were me - I would cancel the blood test and go back to 100 mg every week and assess in a month. You can tell your endo when you see him (after you check bloods on this dose) that you really felt lousy with less frequent injections. 100 is a good place to start per week. You may have not noticed any increase in libido because of increased Estrogen - which will spike way up at the dose you are on now by the way.
I suspect you 100 mg/week would be fine with an AI like Arimidex - but you can't accurately determine that with the dose you are on now.
You may also want to consider getting bloods done yourself to see how high your Estradiol is - there are some online labs that will send you an RX at some participating labs.