Help!! I can not purchase a new computer right now

I woke up to lightroom crashing on my computer this morning. This has all of my work for the past 6 years and 4 photos sessions that I am currently working on. 

I have a Mac Book running off OS X El Capitan. This is a 2011 mid computer and I can not upgrate my system. This has been working just fine on my computer but now I'm unable to download it. I cannot purchase a new compouter right now. I'm in such a huge bind. Can you please help me?