How can I get this under control? 10 points?

Ok well I am an IB student, not to brag, but to help you understand the situation im in. i have 4 tests left tomorrow two in french and two in environmental systems. while environmental systems should be easy french prbly wont be. Ive gotten 4s and low 5s on my ab initio french practice tests and i havent really studied for those. I am concerned that I might get a 3 in both and since they are both SL exams this would cause me to fail the IBs. Failing would result in me not going to Germany to study but going to Germany to work a decent job with a decent wage (just like most other Germans). So failing would pretty much be a total mess and chaos for the future of my life. I was wondering what the percentages were for the different papers, internal assessments, etc. that determine your end grade? Also if i have a 3 in an HL subject but equalize it with a 5 in another HL subject can I do the same in an SL subject or can you only equalize a 3 once? Oh yeah, and if you fail a test and don’t receive your IB diploma cuz of it can you retake that test and if you pass can you still get your IB diploma just later? And how am I supposed to cope with this stress, because these tests will determine my entire future? THANKS FOR ANSWERING PLEASE ANSWER ALL OF THE QUESTIONS. THANKS AGAIN!!!!!