It seemed to go wrong when I installed the pirates of the carribean game update (a horrible update that is so glitchy it doesn't actually work), it sounds so stupid that it must be a coincidence, but I know the play store app was there before I installed that update as I used it to get the update, then I played around with pirates, trying to get it to work, then I went to go to the play store to place a new review on it and play store was gone (the icon at least, it was still in manage apps at that time) I decided to click uninstall update on play store, hoping that when it reupdated itself fairly quick as the old market used to the icon would reappear. That was my main mistake I suppose lol.
I was worried about that with the apks, I will have to look into it carefully. In the meantime I will keep hoping that market updates back to play store and the icon comes back.