Okay, well... Here is the information, broken down into categories/questions you asked!
what happened between Eklavya and Kt's wedding.
Well, basically.. KT was consoling Lakshya, and Eklavya caught them, and thought she was 'flirting' with him or soemthing, like suspected her, and almost slapped her once! Lakshya tried to go in, and clear out the problem, but Trupti stopped him!
And Sanchi and Nakul
Nothing really happened with them so far! Sanchi just came back in the show, after a month or so I think!
. And I just wanted to know where is Mihr? Is he still with the family?
Mihir is arrested for the 'murder case' which was all Rishabh & Trupti's plan!
So, I suppose he's supposed to be hanged, meanwhile, the Virani's are kicked out of Shaanti Niketan, which is now owner by Trupti.
And where did Bhoomi and Manthan go?
No clue about Manthan, I miss him so much!
Bhoomi was shown some episodes earlier, don't really know about right now though!
And Damni and her child who was a bit mental (I forgot the name)
Mayank! Well, he's still supposed to be the Mental Assylum I guess! Actually, the actor who played Mayank's character, had quit the show long time ago.. So I guess that track is completely gone now!
Hope this Helps!