I was on the depo-provera shot then changed to desogen (ethinyl estradiol and desogestrel) but stopped due to nausea so how long should bleeding last?

Hard to say: Many women will bleed for as long as 3 months with depo-provera, despite taking the Desogen (ethinyl estradiol and desogestrel) or not. It will generally improve with subsequent injections, but can take a couple of shots to improve.

Varies : Depoprovera can last in your system for up to one year. For those who have bleeding and spotting with Depo-Provera it can be very frustrating. Eventually it will wear off. Switching to birth control pills may be helpful but it may take a few cycles.