How to deal with the fear of missing out? I will be soon starting my Ph.D. but have already experienced some of the research environment. I have chosen to work on a field in machine learning that is becoming increasingly popular. Every time I see people publish something new in this field, I cannot help it but feel like a loser who missed out or has lost the opportunity to publish that others did. I feel like when I catch up and have the necessary skills, everything would have been already discovered.
This is a downside of working in a "hot" area. But it is also why you have an advisor to guide you. In reality you can't do everything and your research will be (should be) deep and narrow. Therefore a lot of the stuff flying around you just isn't especially relevant to your research, provided that it is properly grounded. 

Focus and treat all the other stuff as noise. Once you get some research published you can think about broader issues and where you want to take you next deep dive. 

Don't completely ignore the general work going on, but don't be overly concerned if others are picking apples in the same orchard. Only get worried if it seems like others are making progress on your problem faster than you are. Your advisor should be able to help with this. But nothing is guaranteed. There is a lot of parallel work going on in hot areas.