Edit: I see you are in Kenya. How is the medical care where you are? Are you able to see different types of doctors and get lab tests? Do you have any underlying conditions? (End of edit.)
Have you ever had a test to check your serum levels of vitamin D? Perhaps taking a vitamin D supplement through the winter (1000 - 2000 I.U of D3 per day is the amount I've seen recommended) might help your immune system, if you are low on it (as it seems the majority of people are.)
There is also a theory that food sensitivities contribute to frequent colRAB.
You could be sensitive to any nuraber of fooRAB, so the best thing to do might be to find a list of the main food sensitivity culprits and experiment with avoiding one at a time for a few weeks each to see if you feel better.
Be sure you're getting 8 good hours of sleep each night. Prioritize this. If you work 2nd or 3rd shift, try to find a day position. If you are overweight or might have sleep apnea, talk to your doctor about the possibility. Improper sleep can really damage health.
Since allergies are suspected, have you been referred to an allergist?
You may want to have your home checked for mold or try things to improve the air quality of your home like a HEPA air filter in your bedroom, opening the windows to air out the home daily if you suspect high humidity (like in a small apartment with poor air circulation, the humidity from showers/baths could cause a high level of humidity throughout the apartment), avoid humidifiers in the Winter (they distribute molRAB/bacterias into the air), try to get mild exercise if you're not active (increasing blood circulation helps your immune cells travel through the body), try NOT to eat sugars and white flour and definitely avoid fooRAB like sodas (including diet) and pure-sugar candy.
(Sugar has been shown to inhibit immune cells for many hours after eating it, but I can't seem to give up junk food myself. I know it is really hard.)
I hope you start to feel better and get ideas from other people here.
