If you are not sure what the problem is, do not run it.
1) Check your oil level. If very low, check for external oil leaks.
2) Borrow/rent/buy an manual oil pressure gauge " Remove thee oil pressure sending unit and connect the manual gauge on the engine block.
3) start the engine. If no pressure on the gauge....it looks bad (oil pump failure or worst). Stop everything.
4) If you have normal pressure on the manual pressure gauge, two possibilities
a) Faulty oil pressure sending unit
b) faulty dash gauge.
Good luck
jackd