i had the same issue, Oil light, stopped right away, checked oil and coolant was fine. Started again but rattling. so turned off. Lucky i was about 500 metres away from a garage so started and drove very slowly to them.
They confirmed it, cleaned, flushed and since then 12 months been fine.
Only issue you have is how far you went and how hard with light on, and also fact it now wont start, that said its a starting point and hopefully the issue