Creeper blowing up when entering nether causes is portal duplication and ignition

I was running from a creeper and it went through my nether portal. So I went through (dumb idea lol) After it exploded when I entered the nether my portal broke and duplicated two blocks back and ignited while the original was de-ignited. LAstly I hav a portal 16 blocks the wrong place  I am not going through cause I'm worried help. Plz thx