Replacement hip feels like it is going to dislocate

My 8 year old replacement hip has suddenly started to cause issues. In certain positions/angles, it ‘feels’ like the joint is going to dislocate and then it suddenly ‘snaps’ back into place, causing immense amount of pain.

When this first happened, the person I was with was so concerned with my grey pallor, that they were about to call an ambulance out for me.

Anybody else had this issue and what did they do about it?