I just took mucinex dm with my zoloft, looked up drug interactions for my propranolol and found out i just set myself up for ss, what should i do?

Drink water: Drink plenty of water and eat a meal. You are unlikely to get serotonin syndrome after one dose of mucinex DM but you do need to avoid dextromethorphan if you are taking the zoloft. If you develop a fever, muscle pains or other symptoms see a doctor right away.

That doesn't mean : that you will develop Serotonin Syndrome. It just means that there is a potential it could occur when medications are used together. I have seen serotonin syndrome very few times during my career.