Hey Prashansa.

I'd suggest you to join any other college that you have as a back up or any other options that you have. If you have any other Private or other law college in mind then you can join it. Or even if there is any other college for other graduation course like BA/BCOM/BBA/BSC etc. You can prepare for CLAT simultaneously in your first year and attempt it. This would be better than taking a second drop. In this way if you crack CLAT you can join the NLUs and in case you don't you will have a back up option to continue without wasting any year. If you join a graduation course you can complete it and then go for 3 year law course in top colleges like DU, GLC Mumbai, ILS Pune etc.

Otherwise if you want to give another try to CLAT you should, but with joining a college would act as a good backup for you. Many people do that. Along with CLAT you can fill other entrances too with good law colleges.

Best of luck