Like RBarron said its probably just mucus. I know as the day goes on mine tends to get thinner and more like water but that is because I drink a lot of water during the day which tends to thin my cervical mucus. But I would just call and mention it to your MD to be on the safe side if you have any more blood in it. Good luck.
I have been having clear mucus off and on since about 20 weeks. I haven't had any blood, and my doctor said it was nothing to worry about. I really thought that it is part of my mucus plug, but the doc said I was probably fine. He didn't do a pelvic exam or anything so I guess if he is not worried, I shouldn't be either...
Good luck.