6mo diarrhoea

My baby just turned 6 mo. He has been pooing 4-5 times a day for the past 4-5 days. Paste form. He used to poo once or twice every 4-5 days. Is he having diarrhoea? Should I be worried? He does not seem lethargic, still in good spirits, still drinking well, not vomiting. Fontanelle does not seem more sunken than usual.