My man, as a person who has done medical attachments in the polyclinic I can assure you that you don’t have to tell the auntie receptionist anything at all. At worst, the person at registration might ask you why you’re here just to prioritise you in case you’re coming in with something like a heart attack. Even if so, just say that you’re down with the flu. Once you see the doctor, privately in the clinic, tell him what’s really up. Polyclinics also have in house psychology services and doctors themselves can manage baseline GAD (if that is indeed what you have). That being said, if your condition is serious enough that it causes suicidal ideation I would suggest getting this fully worked up regardless of the cost (public healthcare system still cheaper or at least same price even w/o subsidy) or you should try making time to go see a doctor in your home country. Nothing is more important than your mental health my dude. All the best hope you get better.