Hello,
It can be due to yeast infection. Try to avoid wearing tight underwear and pants. Wear cotton underwear as much as possible and maintain proper hygiene. It would be best to see your Doctor so a pelvic examination can be performed. A sample of the vaginal discharge may be taken to confirm the specific cause of the infection. If a yeast infection is confirmed, an antifungal medication will be prescribed to you.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
My first thought is a yeast infection, since those tend to itch like crazy. If you've been scratching/rubbing a lot, that could cause a rash and maybe a little bleeding (enough to turn the discharge pink). You should go get it checked out, though. Yeast infections are easy to confirm and easy to treat, but if it's something else, you'll want to know sooner rather than later.