Hi @Pex
The index is big because you sue really big images. The entire Index page loads over 16.5 MB 
This should be below 1.5 MB .
to give you an example : 
The above image has 1.9MB
In case you would optimize it, and instead of using a PNG, you would a jpg version (the images doesn't need to be transparent) + you would optimize the JPG image version you can easily end up with an image which would be a fraction of it, like 250-400KB.
Once you solved all your issues with the images the site will load way faster. Lazy loading is an option, but I wonder if somebody would build that in into your slider module
https://developers.google.com/speed/pagespeed/insights/?hl=en&url=https%3A%2F%2Fthemegamart.in%2F
The above is a Google Quality score!
Start optimizing your store, a s soon as you can;)
