IP address change counts a big change for Google, give it more time and you will be back to the SERPs.
I wouldn’t advise to upload lots of content at the same time, one big change is enough for Google, try to upload the new content in little bits, not all of them at once, that might seem suspicious for the big G along with the IP change.
Don’t give up, it is just a temporary decline after drastical changes, it takes time to settle the things back on track (2-3 weeks at least).
Hope it helps 