Cant access some websites on all web browsers. help. Virus maybe?

Hello apple community. I had this problem started yesterday in getting access in some websites that use to visit. e.g. yahoo.com.

its not only yahoo, there are others too that i cant access.

i am inside my apartment, i have my own internet connection.

the internet works fine on other site, i can even use youtube very well. facebook also works but not properly work the way it use to be.

the internet connection is not slow.

when i type in yahoo.com, it doesnt automatically prompt that i have no connection or something else but it just load and nothing happens.

*also happens on website i usually go, it just load and nothing happens for hours.

I tried it on other browsers, FF, chrome and safari. All are just the same.

i tried it in my iphone, it happens too like in my mac doesnt.

my wifi is secured, had a password on it.

another thing is my mail app in my mac, i have 4 email accounts on it but the icloud account cannot connect to its server.

i am afraid that this might be virus in my modem or router?

i tried it on my other windows pc, still same result.

what should i do? thanks.