Cough & Cold plus weakness. Is bad : (

I recently faced issues of nausea at office and also vomiting after lunch. It was my first time getting that feeling. I came home and i thought of sleeping over to get better but it didn't really help. So at night i went to see a doctor who said i have dehydration and prescribed me some antibiotics and acidity & vomiting medicines. Took a three day course but again yesterday at night i started sneezing badly, had a choked nose and also could feel a bit of fever because of which i couldn't sleep at night. Don't know what it is but whenever i cough i could feel it in my chest like all jammed up. I was feeling of getting some blood tests done. But i don't know which ones should i go for. Please let me know some solution on this. Being sick is bad :(