Should I give up on pursuing a PhD in Europe if I performed poorly in my master? I'm currently a master student in an Erasmus Mundus program. Unfortunately for me, I have been doing badly. My overall grade on the first 3 semesters is a C. So far only my master thesis remains but I don't think even an A will make me go from a C to a B. Is it worth trying to apply for PhD positions or should I just give up and go to the industry.
Anecdotal answer: I did pretty horribly in my first higher-level, bachelors mathematics courses, partly for health reasons and partly because I had never been challenged like that before.  I also performed horribly the first year of graduate school (equivalent to first year of masters in Europe).  I had to learn (not re-learn, but learn for the first time) basic proof techniques in analysis.  Not only did I eventually get a PhD, but also subsequent postdocs, and I have a growing number of publications.  Some of us just start off a bit behind and have to work harder to catch up.

At the same time, academia isn't the only place to do research.  There are many research-like positions in industry.  If research is your goal, do research.  You don't need a PhD to do research (but it can help in some cases).