Tumblr Virus?! Does anyone else have this problem and do you have a solution?

I don't know if it's a virus or something, but since maybe 1 week and a half ago, I've been trying to see my followers blogs because I want to see if any of them have any cool stuff and if I should follow them, but now whenever I click on 2 or 3 of my follower's blogs, I'll be directed to some fake tumblr log in site or to some other site called "the IQ society" (i've only seen the iq on one blog though), and I don't know if they're fake tumblrs used for scamming. BUT! Here's the weird part, if I write down their URL on google and I click to see the "CACHED" version, the blog looks perfectly fine, and it even shows them reblogging recent stuff. Is there a virus on my tumblr and should I change my password? Ohhh! And I've already scanned my computer like A BILLION TIMES but nothing is ever detected! What should I do, and does my tumblr have a virus? i don't want to delete it! Help :c