college junior looking for advice

This is my first post on here ever, so please go easy on me. (Also, I had one of the worst days of my life and the rejection call I received tonight was just a cherry on top, so please forgive me if I sound too emotional). 

I am a junior at a top 15 semi-target interested in management consulting. I made it my mission the beginning of this summer to land a consulting summer internship either at MBB, big 4, or a reputable boutique. I don't have any "prestigious" extracurricular experience, but I do have a lot of work experience, and the skillsets I have are pretty relevant to consulting (at least in my opinion). I networked a fair amount and made it a point to at least form a meaningful connection with three people at each firm I was interested in, cased a TON (probably 40+ cases total), and tried to tailor my resume towards consulting as much as possible. Yet, when the time came to apply, I found myself rejected at the resume screen from MBB, boutiques, big 4 firms, and got one offer to interview at one of the big 4, but received the rejection call tonight. 

I feel like I am in this horrible loop where I apply to so many places and clubs and organizations, and I hardly ever see any acceptances. To be completely honest, I have spent more time crafting applications and networking than I have on my schoolwork this semester, and it seems like it is all for naught. I don't know if this normal or not, but I feel so isolated in this process, especially whenever I see other people who have not worked as hard as me get positions (and I am not just presuming this--a lot of my friends did not network and did not begin practicing casing until this fall). Obviously I am happy of them and I don't want to come across as entitled, but I guess I am just unsure of what I am doing wrong and unsure of how to get better. 

Friends, I need advice. What type of extracurricular opportunities should I look for? What are other firms I can still apply to that are either directly related to management consulting or consulting-adjacent (M&A advisory, corporate strategy, etc)? What can I do in between this year and the next recruiting cycle to increase my chances for landing MBB or big 4?