I have installed the cache plugin, lazy loading for the images, changed the images parameters in WC plugin setting to fix the problem with image resizing (but you need to regenerate all the thumbnails!). But you also need to contact your hosting provider because even with default theme the site speed is too slow http://prntscr.com/hpoe8bhttps://tools.pingdom.com/#!/LfHWf/http://hvcreations.in/ , I have waited since eternity began to open backend (our theme does not affect the backend).
So, any plugins won’t help you if you don’t solve the problem with your server.
You may enabled the default WordPress theme and check the speed of your site. You’ll see that even when the default theme is activated site is slow. It means that our theme is not the reason of your problem.