I Am 57 & Have Been Taking Testonerone Shots Every

I am 57 & have been taking testonerone shots every 2 weeks for a year or so. I went for routine checkup & got results back of 70 testonerone, but I have been busy lately & have not gotten shots regularly. My doctor referred me to a urologist even though he is aware I had missed my last shot. Could it be normal to drop that low by missing a shot?