Dear Nakul,

First of all, don’t stress out, every problem has a solution if you just think it through.
Now, If seats are available in the same college during the first year and with the agreement of the principal and linked university, one may switch to a different stream. Please get in touch with the college or university's office. Additionally, it is possible to switch your college and stream.

And if that is not a option you have, you can always withdraw your current degree and join BSc program freshly. Remember, if you do it right, it’s never a waste of time.

Also, if you’re interested you can do dual degree at the same time but that’ll make your schedule a bit of hectic. You can do regular course with a correspondence course.
But if you want do regular Bsc course then study hard for the entrance exams like CUET, Delhi university etc then you’ll get into a good college.
Here are few best colleges that offer Bsc in India -

- University of Delhi ( Many college comes under DU)

- Loyola college , Chennai

- Presidency college , Chennai etc

Here’s a link consist of various college -

https://university.careers360.com/colleges/list-of-bsc-degree-colleges-in-india

All the best.