I'm on my third day taking doxycycline mono 100 mg tablet last night I took a couple shot of Amsterdam. Is this bad?

Probably OK. I don't understand "Amsterdam" shot -- maybe some sort of street drug? It probably won't interfere with doxycycline or treatment of your infection. Just be sure to continue to take the doxycycline as prescribed. If in doubt, contact the clinic or doctor who prescribed it.