This is a temporary phenomenon. Don't worry too much about it, but don't act out on the increased libido, if you know what I mean. Conserve the energy. What is essentially happening is that your Mooladhara (root) chakra is more active than the others, which leads to feeling more sexual. With continued meditation, it will be sublimated into a more refined, compassionate, loving-kindness type energy. In Tantra, we use practices of directing even sexual energy towards the inner Goddess; that way, the lust is sublimated into love. You can even visually act out your sexual desire with the Goddess. Certain yogic techniques known as bandhas also help redirect the energy upwards. Make sure your diet is bland and non stimulating. Avoid caffeine, tobacco, alcohol and any drugs.
There is some excellent, free information on Tantra on the
AYP website and forums.
Good luck.