Struggling with criticism from grad student (vent)

Hello all, Im a sophomore undergrad at a lab and have been there for about 3-4 months. Prior to this, I had zero formal lab experience and a very shallow understanding of the science we do in this particular lab. My mentor has been exceptional and is beyond helpful and kind, but I still feel pretty unfamiliar with all of the background science and find it hard to not be overwhelmed when doing my own research. Because of this, I make sure to ask for advice from everyone in the lab (during appropriate tines of course) hoping to gain new insight. So far, everyone has been kind and understanding besides one grad student who has always been somewhat snarky, but I took that to just be his personality. Today, since my fall semester is starting soon and I will be taking four courses, two of which are very rigorous, I wanted to ask him about his study methods and how he managed time to get to where he is. Hes incredibly intelligent and does really cool work, but his answer was not at all what I was anticipating. He compared me to another student (11th grade) he had during the summer stating that he did much more than me, was more involved, and even conducted his own experiment with little to no guidance. He then proceeded to tell me just to read papers and "do more". Its strange because we dont really see each toher often (labs are far apart), so Im not sure how he would know what my progress even looks like. I was already feeling kind of poorly about my performance, since I work part time, volunteer, and also recently had a major life event take place that caused me to burn out pretty badly, causing me to go on "auto-pilot" on lab work for a while. Anyway, after a little cry (when I got to my car of course) I feel embarassed about asking to see his work or what anyone is up to, even though theyve always been happy to show me. I also feel even dumber than I usually do. How do I go about in recieving this criticism and "doing more" in the lab? My mentor assures me Im doing well, but Ive been feeling inadequate for some time now and finally got the courage to ask someone whos work I love and got...that. Any advice about navigating these feelings or just similar stories would be highly appreciated. Thank you!