Since there is doubt whether you saw a pinkish stain on the toilet paper, it may be disregarded. It is not clear where you may have seen the second pink stain. Please get back to clarify if it was a surface other than toilet paper.

You should not perform a bedikah unless required (i.e., during the clean days, or on an onah). A bedikah is treated stringently and even if the staining you found was acceptable, a bedikah with the same shade of blood could render you niddah.

For the future, you should take precautions against becoming niddah from staining while you are tehorah by wearing colored underwear or disposable pantiliners and waiting at least a few seconds (ideally 15 seconds) after urinating before wiping. This way, stains found on toilet paper may be disregarded.

Please feel free to get back to us with any further questions.

This response has been updated to reflect the rulings of our current Rabbinic Supervisor, Rav Kenneth Auman, regarding waiting before wiping.