Media Offline

Hi!
I have been using Davinci resolve 15 for a few months now and although being a complete newbie I've found it pretty easy to find my way around and "resolve" any problems. However, I have 4 new projects which i completed editing yesterday. I have come back today for final touches and they are all showing as MEDIA OFFLINE in RED. I can open them but no view, nothing comes up just red
i have tried rendering one of them but playing it back just plays a big red MEDIA OFFLINE. I have tried closing everything event my mac, restarting and its all the same MEDIA OFFLINE. I'm worried I have lost them. Please tell me there is a simple solution :/
thanks in advance
A
I have been using Davinci resolve 15 for a few months now and although being a complete newbie I've found it pretty easy to find my way around and "resolve" any problems. However, I have 4 new projects which i completed editing yesterday. I have come back today for final touches and they are all showing as MEDIA OFFLINE in RED. I can open them but no view, nothing comes up just red

thanks in advance
A