I believe the "I've got a bottle of your blood inside me" is a reference to wine, not being pregnant. She addresses the beginning of the verse to God ("Lord, you just dropped me here by the side of the road") and so I believe she means a bottle of Jesus' blood, e.g. wine turns to blood for communion.
I believe the "I've got a bottle of your blood inside me" is a reference to wine, not being pregnant. She addresses the beginning of the verse to God ("Lord, you just dropped me here by the side of the road") and so I believe she means a bottle of Jesus' blood, e.g. wine turns to blood for communion.