It's very normal to feel down and depressed during rainy and cloudy days.
When the rain is coming down and the clouds are covering the sun our bodies produce less serotonin which helps to boost our mood and make us feel energized.
During the rain and cloudy days the body produces more of Melatonin which can decrease our mood and make us feel like sleeping.
Sunlight also provides our bodies with Vitamins that our body needs to help boost our energy and mood and when the sun is not out then we get tired and depressed.
You could try a SAD lamp which can help boost your energy and mood during cloudy, rainy or even cold days.