Internet doesnt work and then works all of a sudden

My internet is working for a while and then all of a sudden the internet stops working. I dont get an icon saying tht my internet is disconnected or anything..But when im on the internet i start off with google where I can go to the website easily..but then if i want to go to some other website like for instance "facebook" then it would take me some time to open the website this never use to happen before it use to be fast before...it started to happen some days ago...Is it a virus or something? :s

 

also sometimes facebook works fast for me but most often it has been slow

 

sometimes it takes time to open google as well...to open a website i sometimes have to click on that site a couple of times to make it open or i have to refresh many times as well.