Tammy Lynn Michaels says she was "blindsided" by her break-up with Melissa Etheridge.

But she's gathered herself together enough to fight back and file for full custody of the pair's twin children, Johnnie and Miller.

While Etheridge asked for joint legal and physical custody when she initially filed for dissolution of their domestic partnership, Tammy has taken the battle a step farther: she wants full custody, reports TMZ.

Michaels carried the twins to term, following a donation by an anonymous sperm donor.

Tammy has also asked the court for spousal support.

Both sides of the former couple cited "irreconcilable differences" as the basis for their split. They became domestic partners in August 2005 and things will likely get uglier before they get better.

Tammy's lawyer says his client has $4 to her name and: "Melissa has not been treating Tammy or the children as if they are a wife and children, financially and otherwise."

There is a major hiccup, however: Etheridge and Michaels were never technically married. Therefore, the former is not on the legal hook for a single penny once the partnership is dissolved.