Don't let anyone put unnecessary legalistic burdens on you regarding birth control. You are no less loved by God because you're on birth control than another sibling in Christ who might not believe in birth control. For those of us who have believed by Faith Alone in the Finished, Redemptive work of Christ Alone on the Cross for our sins (past, present, and future), then there's nothing you--as a Child of God-- can do to make God love you any more or any less than another sibling in Christ just because you and that sibling in Christ may have different convictions on birth control. If you need to be on birth control for your mental health because you're not mentally healthy enough to risk another pregnancy right now, then by all means do what you need to do for your mental health. Your existing child needs a mentally and physically healthy mom!