Why did i gain weight while having a cold/bronchitis symptoms? i haven't been eating as much so why would i weigh more?

Most episodic weight change is based on water retention/loss. Overhydrating during minor illness is common. It usually sheds in the short term. True weight gain is triggered by increased intake above energy consumption.

Agree with Dr. Ferguson. In addition to water retention, lack of activity may have added fat as well. If you are well now, it would be important to resume or start regular exercise. Wish you good health!