Q: safari

i bought my first macbook pro last month. whenever i touch safari to do something, the extra page always popping up. every single time let say i hit a like on face book page the other page automatically open. i have to close that and than hit like like again. i want to play a song on youtube i hit play the other page open up. o have to close it and play the song again every single time. i can't even use the safari now. it is so annoying. do i need anti virus or what ?