I think you have to "practice" what you want. You can't have what you don't believe you can. It is good you realize it is related to the juniors so long ago and that they're "gone" now. Think of what you want to do and remind yourself that they're gone and what you want is "for" you. It got much easier for me when I turned around things and saw that, that how hard I worked on my courses in graduate school, what projects I chose, what jobs, etc. could be "fun" and interesting because it was me choosing them for myself. You're not in competition with anyone else, just have to decide what you want and work at getting it.