Hi Aluth,
I understand you enabled the iCloud Photo Library beta on your iPhone, and now you don't see any of your photos or videos. The resource below will explain what happens when you enable iCloud Photo Library. I've highlighted the key information here for you. Click on the article for complete details.
iCloud Photo Library beta FAQ - Apple Support
https://support.apple.com/en-is/HT204264
iCloud Photo Library is available with the new Photos app for iOS 8.1 or later.
After you enable iCloud Photo Library, your photos and videos are automatically uploaded and stored in iCloud.
You can access your entire library from any Mac or PC at iCloud.com/photos.
If you choose Optimize Storage, iCloud Photo Library will help make the most of the space on your device, keeping your full-resolution library in iCloud and storage-saving versions on each device.
The Camera Roll and My Photo Stream album are replaced with an All Photos album, which gives you the same compact scroll view, now with all your photos and videos organized by the date they were added. Learn more about finding photos in iOS 8.
After you enable iCloud Photo Library, all your original photos and videos are organized in one library. My Photo Stream will upload recent photos to share with your other devices, but iCloud Photo Library stores your originals. See how to upload originals below.
If you turn on Optimize [device] Storage, iCloud Photo Library will automatically manage the size of your library on your iOS device, so you can make the most of your device's storage and access more photos than ever. iCloud Photo Library stores the original, high-resolution photos and videos in iCloud and can keep lightweight, device-optimized versions on each of your devices. As long as you have enough storage, recent photos and videos that you access the most will stay on your device at full resolution.
To turn on Optimize [device] Storage on your device, tap Settings > iCloud > Photos or Settings > Photos & Camera, then select Optimize [device] Storage. You need an Internet connection to access an original photo or video that’s stored only in iCloud.
I hope this information helps ....
- Judy