Cannot use iCloud Photo Library from iPhone?

I recently disabled iCloud Photo Library because it stored all my photos from my old iPad which I no longer needed and there was no available space on my iCloud. I decided to purchase the 50gb iCloud and now I would like to enable iCloud Photo Library from my iPhone so that I can store my photos there.

I tried to go to Settings -> iCloud -> Photos and enabled iCloud Photo Library but after that nothing happened. I think it should have started to sync my photos to iCloud but it did not.

I checked iCloud Photos from Safari and it says the following at the top of the page: 'iCloud Photo Library has been disabled. You have 15 days remaining to make sure you have a complete copy of your photos and videos.'

I think it's because I disabled it half a month ago and I would like to know whether I have to wait for 15 days to be able to enable my Library again or there's some other solution.