Cant seem to shake this flu?

ive had the flu since 20-21 july and i cant seem to get rid of it. headaches, runny nose during the day and a blocked nose during the night, joints aching, watery eyes, dizzyness, occasional nausea and its flaring up some asthma which also isnt good, and i cant seem to get rid of it! ive been on 2 lots of anti-biotics, cold & flu meds and 2 asthma puffers, and i cant seem to get rid of it. also tried rest, been drinking lots of fluids, appetite hasnt really been great. any other ideas? been to the doctors alot coz it just doesnt seem to get better, and i dont wanna go bak to the doctor. anything else?