Sagittarius + Capricorn?

Almost every girl I've dated had fire in either the sun, moon, or venus signs, and although my current girlfriend is a Capricorn in the sun sign, the rest of her signs are:

Sun: Capricorn
Moon: Aries
Mercury: Capricorn
Venus: Sagittarius
Mars: Capricorn

While my signs are:

Sun: Sagittarius
Moon: Taurus
Mercury: Scorpio
Venus: Capricorn
Mars: Cancer

I wonder how compatible this connection is? We have a lot of fun when we are having fun, so we enhance each other's energies. However, it works the opposite way as well. Whenever one of us feels negative it brings the other down, although I usually try to stay positive but it is hard >