Hi zonabi,
a cold or similar illnesses affects your etheric body quite a while bevor it manifests in your physical body. So it's better to eradicate any disorder there, before it goes "down" to the physical. It is useful to develop consciousness at the etheric level of your being, because it's the part that gets affected the most i.e. because of energy-draining and polluted people/crowds. I think techniques like qui-gong or tai-chi help one to gain some consciousness at etheric level. I did develop it without any traditional technique. Now that your physical body is ill, you seem to have to go through it, I guess... The means already stated will surely help - garlic is indeed a miracle cure. Remember it's said to
be protective against vampires. 
A meditational technique I practice when I feel energetically weakened and polluted is 1. breathing through the etheric body. It cleanses and strengthens it. 2. grounding! I do it that way: focus your consciousness at the soles of the feet, locate the root-chakras. keep concentrating on them until the feet become warm. You aditionally can imagine light floating from all sides into the chakras, making them grow... Then, imagine shining "roots" from the chakras that grow deep into earth. You'll perhaps already feel a difference... Then, I say hello to mother earth
and ask her to take the "dirt" off of me. One can intensify the process through imagination - guide the pollution out of your body. If you feel it's enough you can turn the process around - gently suck fresh energy up to you, whether by imagination or through direct guidance of energies (similar to aura-breathing). That's it. Don't detach the connection - from my point of view it's a natural state. "Mother earth" nourishes us anyway - if physical or by etheric energy.
In principle one could suck energy in through every chakra, but one have to be cautious because that may cause disbalances/disorders. I regard it being safe as I described above - one can also do the process by utilizing the base/root chakra.
A man is born gentle and weak. At his death he is hard and stiff.
Green plants are tender and filled with sap. At their death they are withered and dry.
Therefore the stiff and unbending is the disciple of death. The gentle and yielding is the disciple of life.