You are right in putting your friendship aside. Either the friendship has served its purpose, or you can deal with the friend at a later time and rekindle the friendship if you feel it is the right thing to do.
Regarding your job, you are describing an interesting pattern that I have observed with many people. It is time for you to leave that job, and the people who are treating you the way they do are in their own miserable way telling you that it is time to leave.
I have seen so many times that when you get those signals, you can resist and try very hard to make the best of the situation, but chances are 95% that everything will get worse rather than better.
On the other hand, when you let go of that job and become willing to accept change, a new and better job normally appears like magic and all you need to do is accept it. When you are in that situation where you feel dependent on the job because you need the income, it does become difficult to see other options.
That is why it is so important to trust and have faith and accept the change. The first step is for you to accept that you are OK and taken care of, and start looking out for the job that is waiting for you.
Yes, dealing with a new job and university and a wedding is a lot, but within the next 2 months you will land on your feet and then you will be able to enjoy your wedding.
And here is another very powerful piece of advice: ensure that you stop at least five times a day and take deep breaths for about five minutes. When you get stressed, you forget to breathe deeply enough, and your muscles tense. When you focus on breathing, you provide more oxygen to your body, and your muscles relax, and this allows you to be more observant and accepting of change and opportunities.
You are going to be a lovely bride, and you will be able to relax and know that your life has changed dramatically for the best. Hang in there and enjoy the ride.