Need help with 1 year old tantrums

Hi guys

My son is 14 months old and he has the worst tantrums when he doesn't get what he wants . He screams and whines . Lays on the floor and cries .

He also wants to be held all the time . Allll the time . I feel like at 14 months old he should play more . Even when we go to the park he stands right by my side and doesn't go and play with Other kids

I've been going to a new gym . They have a great childcare . I'm only there 40 min and he just cries every time when I'm not with him . It's been three weeks of me going and it keeps getting worse .

He also still breast feeding and nursing 10 times a day . Fights me when wanting to eat anything else and doesn't like milk or any alternatives that I've tried .

I feel like a sinking ship lol Does anyone have any advice to gain some control over my one year old lol