I'm really sorry but I'm not quite clear on what you're asking for advice on! If you've had problems with specific lecturers, or you're currently worried about your assessment situation, it might be worth speaking to someone from your SU, as they might be able to support you in navigating retakes etc.
It does sound like there is some miscommunication going on- perhaps it would be best to confirm everything in writing, email would be fine. So each time you have a meeting, afterwards, email the relevant person confirming what was discussed/agreed. This should help give you some clarity. In fact, it might be a good idea to email now, asking whether or not you retake and when this retake will be. If the retake clashes with your holiday, unfortunately, you may just have to suck it up and change dates or cancel- this sucks, but it's also why it's not always a good idea to book holidays in this period.
If you've failed one assessment, will this definitely prevent you from graduating?
Are you getting help for you anxiety? It does sound like this is making everything worse. If you're not, please consider contacting student support or your GP.
Finally, please don't get drawn into commenting on lecturers on social media- this can lead to serious disciplinary consequences. Even if you don't like them personally, try to behave politely and professionally towards them!