It should be. A few months back, http to https migration was simple. But now, because Adsense ads are not shown on posts which are not indexed, HTTP to HTTPS migration has become difficult.
Now when u migrate to https, adsense ads will not be shown till the time google has not indexed ur https site. However, because google knows that many brands are shifting from http to https, they have started indexing https very fast. So u might suffer a drop for 2-3 days. BUt u will see a rise later.