Keep Coding

I have been busy with a follow function. However, "Notice: Array to string conversion in C:\xampp\htdocs\eindwerk6\classes\User.php" on line 364 keeps popping up.
This is the relevant function in User.php:
public function checkFollow($mainID, $guest){
$conn = db::getInstance();
$statement = $conn -> prepare("SELECT COUNT(*) FROM followOthers WHERE followerID=:followerID AND followingID=:followingID");
$statement -> bindValue(':followerID', $mainID); //this is line 364
$statement -> bindValue(':followingID', $guest);
return $statement;
}
This is where I call to that function:
$check = $user->checkFollow($currentUser, $guest);
$countCheck = 0;
foreach ($check as $c){
$countCheck = 0;
}
This is where it's supposed to be used:
if($check->fetchColumn() == 1){
echo "<a class='btn btn-default' href='#'>Unfollow</a>";
}else{
echo "<a class='btn btn-default' href='#'>Follow</a>";
}