This is a bit slangy - the correct version is "No one took over my account, it's just me". Here account would appear to refer to an internet account on some site, possibly a forum, where someone has suggested that an account has been hacked in order to post 'different' messages. It is difficult to give any more advice without more context.

No one took over my account, it's just me". X No one took over me account, it was me . (someone hacked your account I(n the past) , but it WAS just you who logged in (also in the past). No one has taken over my account ( from the time you opened the account until now) , it has always been only me ( You are the person who has been logging in all the while until now) No one is using over my account , it's me.