Hey, I have sold a put option on the Nifty Fifty for this week at 25,950, which is equivalent to 65 shares.
The market has reached approximately 25,690.
I’m not sure what my losses will be, such as if the market closes on Tuesday at the spot level of 25,600. What would be my loss if this is the closing index level? And what could I be advised: should I exit the option now? Will I be able to mitigate the loss in any way? Or should I wait until Tuesday for the option to expire?
350 points(x65) will be your loss if NIFTY closes at 25600,i.e 25950-25600. You may buy a lower put option, to create a “bull put spread”, to limit your losses, in case NIFTY goes down.
If I were you, I’d close position when and if it rises a bit or sell at even more loss, if it goes some more. Sell on rise would be my strategy. In any case, have a predetermined SL placed at the broker app.
Best would be to Roll over to PE25900 or PE25850. You would have enjoyed a premium when you sold PE25950, you can go down in strike to extent of the premium you enjoyed. You should not exit the Short PE as the market may return any time and the loss you booked will become irrecoverable. You can keep your position hedged at weekly or monthly at 25000 levels.
Roll out in time, I would never take a loss on a short put in a bull/sideways market. 
Of course we could enter a bear market and your loss could deepen but the structure isn’t yet bearish and we’re just past a major correction. 
P.S. Not financial advice! 