Some…. read many…. ad agencies are sweatshops. They compete on price, take on tons of work and then have to under pay and under hire to even have a chance of making a profit. Working over time happens a lot….some agencies are way worse then others. Having to do any drugs, Adderall, alcohol…ect , is not a good sign at a job.

I would try to keep applying to find a job that is better for you. I would just be honest when getting asked about why you want to switch. You realized you love X more and don’t enjoy Y as much. Also you want to feel less over worked and tired all the time. Any place… ad agency or in-house… will value this honesty and not want you to feel like mush at the end of the day all the time.