Get IndexPath of CollectionViewCell outside of Cell

First of all I am a newbie in swift, so be gentle. I have a problem fetching the indexPath of the cell outside of the cell. I want to get that index path to a function and use it to send the content to another view. The image was created programatically in the cell, it has a tap gesture recogniser sending to this function (where "myIndex" is defined as an Int : var myIndex = 0):

// tap image to go at the indexpath of the user
func imageTapped(tapGestureRecognizer: UITapGestureRecognizer) {
   print("image tapped")

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let secondViewController = storyboard.instantiateViewController(withIdentifier: "patientProfile") as! PatientProfileVC
    secondViewController.userID = posts[myIndex].userID
    secondViewController.patientName = posts[myIndex].author

    print("Passed data to the other view")

    self.show(secondViewController, sender: self)


}

I know that I could use didSelectItem at IndexPath where I also have the declaration of the myIndex but I have something that will be triggered from a segue there:

//standard functon for item selected
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

    //get the index of the cell
    myIndex = indexPath.row

    print("Cell is selected")

    //perform the segue
    self.performSegue(withIdentifier: "CommentsVC", sender: self)
    print(myIndex)

}

and my perform for segue looks like this:` override

func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    print("Segue Initiated")
    feed.navigationItem.title = nil

    //if segue.destination is CommentsFullVC{
        print("Comments segue initiated")
        let secondViewController = segue.destination as! CommentsFullVC
        secondViewController.questionData = posts[myIndex].postContent
        secondViewController.authorName = posts[myIndex].author
        secondViewController.date = posts[myIndex].normalDate
        secondViewController.profileImagePath = posts[myIndex].pathToImage
        secondViewController.typeOfClinic = posts[myIndex].clinic
        secondViewController.postID = posts[myIndex].postID
        secondViewController.followersForPost = posts[myIndex].followers

}

So my question is, how do I pass those 2 fields to the other view without using prepareForSegue? I am struggling with this for 20 hours now and still can not figure it out.

secondViewController.userID = posts[myIndex].userID
secondViewController.patientName = posts[myIndex].author

UPDATE: Got it to work thanks to Jose answer, now it looks like this... in case anybody has the same problem as I had.

 // tap image to go at the indexpath of the user
func imageTapped(tapGestureRecognizer: UITapGestureRecognizer) {
   print("image tapped")


    let pointInCollectionView = tapGestureRecognizer.location(in: collectionView)
    let indexPath = collectionView?.indexPathForItem(at: pointInCollectionView)
    print(indexPath!)

    // this one works - show segue
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let secondViewController = storyboard.instantiateViewController(withIdentifier: "patientProfile") as! PatientProfileVC
    secondViewController.userID = posts[(indexPath?.row)!].userID
    secondViewController.patientName = posts[(indexPath?.row)!].author

    print("Passed data to the other view")

    self.show(secondViewController, sender: self)


}