Hi Chloe101,
I also was in your shoes, just a week ago. It's not easy, but you can make it. I know, that it's hard to find something good in all of this, but you are still a great person, an excellent and hard worker and no matters what the reason was, that is thier lost, not yours. As already said, keep your head down, try to not show your emotions, do not make any comment to anybody elses, you know yourself, people who are still there are there becasue they fit the sick culture and atmophere. Focus on keeping your options opened and be kind to yourself. You will see, you will back on your feet. Take it as a hard life lessons, there is lots of bad eggs in any work places. You are in charge with dealing with all that, but you can manage. During my notice time, even that I felt like explode, I showed them that I am the adult over here, I was nice to them and respectfull. I walked out with my head up even that I felt like cry. If, you can afford it, maybe bring some cookies on your last day and say big thank you to the "lovely" senior manager for giving you the opportunity to do this job, tell him that you would be happy to use these experience in your new role. About looking for a job, do not mention to anyone and try to not take time off for interviews, remember, they are nasty and you do need any more stress as you already have.