There seems to be a common belief that the children must come first in a person's life. To some degree this is true, as the infant is completely dependent on you for everything: feedings, attention, clothing, changing, etc. However, many couples take this to an extreme, resulting in a disconnect in their relationship. While you never want to neglect the needs of a child, you also do not want to neglect your own needs... you're only as good of a caretaker to another as you caretake of yourself.
Prior to children, you might have been a wife/husband, employee, and good friend. Adding in a role of parent may be a juggle, but that additional role should not replace the other roles altogether. If you find you have completely given up other roles to add in the role of the parent, it's time to start doing something different. Reconnect with friends, have a date night with your partner, let your partner take care of the children for a few hours and engage in yoga classes. Whatever you do, it's important NOT to lose yourself in the role of parenthood. At some point, your children will be grown and out of the house, keeping your sense of self in tact will help you with all the transitions in life that face you.