Boleh la possible, tapi very rare, depo tu 99% effective, jadi chances sangat kecil! A few of my mum friends pun ada yang worried about the same thing, but honestly if you're concerned, best check with your doctor sebab dia boleh confirm through blood test or scan, takut-takut ada yang tersilap timing or ada health factor yang affect the depo. Don't stress too much, but definitely see your gynae to be sure!