The half life of testosterone cypyonate is 7 days, so you should inject at least once a week, better if you can do 2x a week. The way you do it now, by the day of your next shot you have minimal testosterone in your blood. Ask your doctor for weekly shots or ask him to teach it to you so you can do it for yourself. 400mg is a lot for 2 weeks, most guys are on 100mg/week. If you don't use an AI, you should, high estrogen can cause your problems too. If your doctor won't bother, than find another, because this one seems stupid.