If you think your budgie might be SICK, or if he/she is showing ANY signs of sickness, please TAKE YOUR BIRD(S) TO AN AVIAN VET AS SOON AS POSSIBLE!
Please keep in mind that many times budgies will hide signs of sickness until the very last minute.
If they are already showing signs of sickness, that means that things are already pretty bad. Once a bird starts showing signs of illness, every minute literally counts.
If you have even the slightest feeling that your bird may be sick, please take him/her to an avian vet as soon as possible.