Welcome to HCM.
You have taken 2 shot of Depo Provera so far.You did unprotected sex and got pink blood in the next morning.Now you present with brown discharge after urinating.It is not fresh bleeding.
So possibility of pregnancy
is almost nil and Depot is an effective contraceptive
method with failure rate 0.3 HMY.So don't be much worried.
It is probably due to effect of Depot and it causes irregular vaginal bleeding
,delayed period,nausea & vomiting,spotting,abdominal pain
,psychological upset,headache,wt changes etc. particularly in first 6 months of use.
One more concern that it may causes prolonged infertility
after discontinuation of Depot.So periodical check up is mandatory and consult with your doctor.