That's something that really needs to be discussed with your doctor.
Depo is the one form of birth control that I REALLY try to have women avoid. It's the only form KNOWN to cause weight gain, and bone loss if taken for more than 2 years. It's also known to cause fertility issues and take up to 2 years to even get your period back.
So if there is another form that works for you avoid Depo, it's evil.
Talk with your doctor about the bone loss as well if you've been on depo a total of two years or more.
My husband is on medication that can cause birth defects and I chose the Mirena IUD so that we would be sure to be safe. We're done with kids too, one and done :D I have almost no period on the Mirena so it's a great option IMO.