OCD - blood on book pages?

I need to preface this by saying that I have OCD that revolves around contamination. I've been really worried over the last few months about HIV. Anything I see that looks like blood, I tend to avoid. Well, today I was reading a used book that I had been reading over the last few days, and I noticed brown smear-like marks. I initially thought (hoped) that it may have been chocolate, but after a few pages I saw a couple of small brown dots at the top, and two corresponding red dots on the opposite page. I'm almost certain this was blood. I didn't touch those two dots, but I may have touched the smears, because I tried to not think much of them. I've looked up a number of questions that people had about contracting diseases from dried blood, and they all said that it's almost impossible to contract HIV through dried blood, but my OCD is still preventing me from lessening my anxiety (although it has lessened a little). Can somebody out there please tell me what I should do. Is it time for me to seek professional help?