Thanks for posting your query.
From the information you have provided,
You have had your first Depot
provera injection.
The next dose is normally given after 3 months.
As you have not taken the subsequent dose, you are having withdrawal bleeding. This can be managed with medicines.
Assuming you had taken depot for birth control, if you have not used protection after that , the possibility of a
pregnancy related bleeding cannot be ruled out.
Hence meet up with a gynecologist who will examine you, assess the impact of blood loss on your system and give you medicines to stop bleeding.
If your blood counts are low, you may need iron preparations to improve your
haemoglobin.
All the best, Hope I have cleared your doubts!
Please, do not hesitate to contact me for further queries.