Finding friends as a mum is hard

I've been on this app for about 2 and a half years now, made many connections, spoken to many lovely woman, but everytime a meet up/play date is suggested no one replies, or they simply don't show up and both myself and my children are let down completely. Don't get me wrong, I understand how busy life gets and how plans change but it hurts to not even get a message to say "sorry can't make today..." My sons birthday party had no children show up, not even his cousins, and I feel like a complete failure! My son sits and watches other children play at the park even though I encourage him to join in.. he seems shy and I don't want to push him but he seems to want to play, just doesn't know how because the only person he gets to play with is me... I just feel so lost, Please tell me I'm not the only one 😭