Hi mate,
up until recently, i had two jobs. I do have a girlfriend, which is an important detail. I can tell you, it is exhausting. I did pickup/seduction at work, just because i cant just stop with it. But, also due to the fact that i have a girlfriend, the way i do it has completely changed. While i used to be direct (i am still quite direct, but i just cant walk up to any woman anymore and tell her how much she turns me on. People would talk). Going out was out of the blue, no more energy, and also, i better spend the little time i had with my girl. Although i loved my second job (salesman), i did give it up. I forgot how to live and that is what i am doing now.
So in other words, it is normal. Also, it is your first full time job. You will get used to it and the new rythm. But dont overwork amigo. you work to live, and not live to work. A little hint though: try planning your nights out. you can get a good night sleep in the nights before or after

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cheers