Your symptoms are more likely due to the hormonal
imbalance induced partly by the injection and partly by the failure to take the due dose in time. The menstrual bleeding is a withdrawal bleeding and has taken the form of a polymenorrhoiec cycle. You have two options; either go for additional hormonal supplementation to correct the bleeding disturbance immediately through consultation of your specialist or waiting for a couple of cycles with regular intake of doses to see if the disturbance settles down on its own. Either way, you need dietary supplementation of vitamins and minerals
. Hope this helps.