Will my site lost backlinks after switch to https?

Switch to https only if your site uses shopping cart or some sort of payment processor
other than that, don’t even bother and risk to face some unknown outcome.

Switching to https makes users feel safer on your site, which creates a better user experience, and therefore is preferred by Google. The experts say you will rank slightly higher and new content will be indexed faster.

I switched to https with 301 redirects and there is a brief period where your https pages will be considered duplicates and the old ones will drop out possibly before the new ones are indexed, but long term it should be better.