first I can't believe you didn't just go out and drop a few bucks on a pregancy test from curiousity alone especially since vitex is also know for being a fertility aid. But to answer your actual question here is a good Vitex info sheet stolen from about.com; I didn't notice anything that fit your symptoms, but who knows maybe you've triggered a second puberty.
What is Vitex?
Other names: Vitex agnus castus, Agnus castus, chaste tree, monk's pepper
Vitex is a plant found in Asia and in Mediterranean countries. The part used medicinally is the dried fruit.
Why People Use Vitex
Vitex was used as a traditional folk remedy for a range of female conditions, such as post-partum hemorrhage and to help with the "passing of afterbirth". One of its alternate names, "chaste tree", comes from the historical belief that it can suppress libido.
Vitex does not actually contain hormones. It appears to increase progesterone by stimulating the release of a hormone called luteinizing hormone from the pituitary gland. Vitex is also thought to normalize excessive prolactin levels and promote fertility.
Female infertility
PMS, especially breast tenderness, cramping, and headaches
Acne, especially if it is related to the menstrual cycle
Fibrocystic breast disease
Heavy menstruation
Menopausal symptoms
Side Effects and Safety Concerns
More common side effects include mild digestive upset or skin rash. Other side effects may include rapid heartbeat, hair loss, headache, dry mouth, nausea, rash, itching and bleeding between periods.
Vitex is not recommended during pregnancy. It shouldn't be used by nursing women unless under the guidance of a qualified health professional.
People with hormone dependent conditions such as endometriosis, uterine fibroids, and cancers of the breast, ovaries, uterus or prostate shouldn't take vitex.
Small amounts of vitex could increase the production of breast milk in post-partum women. High doses may have the opposite effect and decrease the production of breast milk.
Vitex may affect levels of the neurotransmitter dopamine. People with Parkinson's disease, schizophrenia, or any other condition in which dopamine levels are affected should avoid vitex unless under the supervision of a qualified health professional.
Possible Interactions
Vitex may decrease the effectiveness of oral contraceptives or female hormone replacement. It could also theoretically increase the risk of side effects.
Vitex could interfere with the effectiveness of drugs that increase dopamine, such as bromocriptine, cabergoline, carbidopa-levodopa, Mirapex or Requip, or decrease dopamine, such as chlorpromazine, clozapine (Clozaril), haloperidol (Haldol), metoclopramide (Reglan), Risperdal, Seroquel, thioridazine, trifluoperazine or Zyprexa.
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