I’m sorry to hear about the loss of your friend.
Many people find stress increases their symptoms, but there’s no conclusive evidence about whether it actually induces relapses - partly because it’s so difficult to study. You’d need to follow people over a very long period of time, and ask them to keep some kind of stress diary. You’d also need to somehow allow for the fact some people get more stressed than others, and by different things. Just a factual diary of events in their lives might not be a good indication of how stressed they were.
I had a relapse following a bereavement - but a few weeks later, not instantaneous. I’ll never know for sure if there was any connection, but I have my suspicions. But as a relapse can occur any time, without obvious trigger, I also have to accept it might have been complete coincidence.
I sometimes find socialising difficult - particularly if it’s going to be noisy and crowded, and not one-to-one. Sometimes having to go to an “unwanted” social event makes me feel worse. Do you think you’re getting a bit wound-up about having to go out tonight? Might be an idea to give it a miss, if you really don’t feel like it.