Dear Tim, 

Yes, a person can be called to the single life without becoming a priest or a member of a religious community. Nowadays especially, there are groups, lay movements in which men and/or women consecrate themselves to God while remaining lay people and exercising their professions. They may or may not live in community, according to the charism of each individual group, but by pertaining to a group they have the advantage of a specific spirituality and way of life to help them live their consecration to God in a way that is approved by the Church. 

God bless.