Internship at a LMM boutique. What's next?

Hello I am an economics student in the south of Europe in a target public university. I am in my last year and I am doing an internship in a LMM boutique, it is among the top 7 in the mergermarket league table with more M&A deals closed (I have signed a contract until August). I am very stressed out because there are very low possibilities that they are going to hire me due to headcount (although they are happy with my work).

Right now I am doing a lot of interviews with different investment banks/boutiques/Big4 but I am not having any luck, I always arrive to the assessment centre but then they reject me, and I cannot understand why! I am very scared that I do not find anything for September.

I would like to point out that I have very good grades, I speak three languages and I have done an exchange program in a French university. So I don't know what may I be missing.

Also, I do not plan to study a master the next year because firstly I would like to work a year in finance and then do it!

Has anyone been in the same situation as me? 

Thank you in advanced