You are losing value of premium due to time decay & rangebound market.... if you short 5300 strangle only then you were in 8.40 profit not loss due to time decay. this is a good strategy to take benefit from a range bound market, now you can cover your 5300 strangle in few points loss before it gives you more losses & remain in 5400 & 5200 position.
PS: I also have short position in 5300 strangle @ premium of rs. 239 & 5400, 5200 straddle @ premium of rs. 169 & both legs are in profit. But i will immediately cover both positions if i feel that market is going to break its range & will shift to another leg.
But remember you will have to track your position whole day to avoid any losses due to Nifty one side movement. This strategy is good only for a range bound market otherwise can give big losses.