How do you get over the feeling you don't belong in consulting?

I switched from biology to economics in late 2019 as a sophomore, and I recruited for Summer 2021 internships in management consulting and economic consulting. During Summer 2020, I interned at several startups in healthtech.

For Summer 2021, I didn't get an offer until May 2021, though it was at a decent EC shop (think NERA, Cornerstone, AG, etc). I also didn't get a return offer at the EC firm I was at.

Also, I literally passed zero of my case interviews during the last recruiting season for internships (Summer 2021 internships). 

I tried to practice harder/smarter for FT recruiting, which is happening now for me, and I got rejected from LEK, Bain, and Capgemini Invent first rounds. I also got ghosted after my interviews at Simon-Kucher (interviewed last Friday, haven't heard anything), as well as at this other smaller firm I interviewed at. 

I recently moved onto the final round at a life sciences boutique somehow, even after taking really long on one question, but I still feel like I'm not great at casing and that as a more inherently introverted person who isn't as confident or outspoken, I won't do well in the field.

Any ideas or advice?

Honestly, I'm just doing consulting because I feel like "anyone" can break in as long as if they get at least 1 offer and provided you get interviews (which I don't have a problem with - getting interviews, I mean), and hopefully after a few years I'll have some money saved to go into more of a "helping" field like mental health or healthcare.