Well brother, I understand your concern. I know you have prepared well and also performed decently in JEE mains. 

But with regarding admission in a low ranking GFTI or NIT

But this, I won't recommend you to join as they 

1. Lag permanent qualified faculty, so their academic quality is very poor

2. Very poor Alma mater of the new NIT's. They'll surely need more 10 years to get stable.

So, I would recommend you with this rank you should look for a decent State engineering college like IET Lucknow or HBTU or state eng. colleges of West Bengal etc.

Thank You