Photo Back Up

I just restarted my Android phone and now there are about a month worth of photos I cannot find. Up until Dec 20th, 2015 my photos were being automatically backed up in the cloud and I could access them via gmail.Are these photos gone? I never deleted them. They were always in my phone over the last month but never backed up to the cloud for some reason. These photos had the circular arrow icon perhaps indicating they weren't being backed up. But why would a restart delete them?I also run out of space on my phone all the time. I have basically no apps on my phone, so what is the deal? I was trying to just get more room for more photos. Very frustrating and I would appreciate any help in the recovery of these photos.Matt