Call your Obgyn right away. He is used to getting calls at any hour and can answer your question. Don't wait. In pregnancy its best to be overly cautious. It may be as simple as something you ate, or not. Call!! now!!
Is it your urine pink or is it blood from your uterus. Big difference. To be safe... Call your dr. I am certain they will set your mind at ease. Some spotting is ok. How long before your next apt? I am sure you and your baby are fine... But I am NOT a Dr and it's always better to be safe than sorry. Call your dr.