Please help me with tantrums!

I need all the advice! My 22m old is a wreck lately. Every little thing sets him off. He will cry and lay and the floor and scream. He will hit and throw crap. I’m at a loss. I try to talk him through it calmly. But when that fails I just walk away and let him scream. But that can last for who knows how long. Today, it was a huge fight getting him in the car seat. Arching his back, crying and etc. I had to get him to preschool in time so I wasn’t late for work. It was a huge fight which ended in a meltdown for both of us. I’m trying to not lose my cool but some days I get so frustrated and at my wits end with the tantrums and fighting me to get in the car seat. I need advice and books on how to deal with this phase. He’s awful at church. And I feel like such a crappy mom for getting frustrated at him and myself.