I just mean that the day after getting drunk, a lot of people feel anxious for no apparent reason. It's an effect caused by the alcohol being processed out of your body, and I normally get it coupled with feeling cold and a little queasy. A very unsettling bodily feeling. When in this state, you still think and make up opinions about things, and due to being in this state you won't be yourself. Even suicidal people some times feel (relatively) good, but when you're feeling down you develop a lot of unhealthy thoughts that come right back the next time you feel equally down.
Some people get drunk twice on weekends, and maybe once or twice a week. Meaning 3-4 days a week you have this sensation, while still having moments in between where you are drunk and feel great. The growing desire to drink more often, the negative emotions you experience the day after, and the contrast you experience from being thrown between these different states, is very anxiety-inducing. It can also form emotional associations to certain times of the day or certain places, which in turn mean that when you're in a specific state there will be places and/or people you may specifically avoid. Anyway, the sum of all this shit is that you CAN get emotionally unstable and confused.