Need advice ladies!

I have a 4 year old who they diagnosed with autism when he was 2. He had therapy every day at home and they let him start pre k and get some help there as well(age3) Last year in December when he turned 4 they told me he no longer needed services because he talk and it was just probably speech delay but he's still had autism. Hes now in kindergarten and doing great! Well in July my husband and I found out we were pregnant again. We were shocked but happy. Especially our son. But my son has super bad tantrums when we're in public I mean he'll throw himself on the floor and scream on the top of his lungs when he can't get something. So much things in public I know he's a toddler and they do these things. But it's gotten to the point where I'm raising my voice everyday because he doesn't listen to his father. From raising my voice so much I've been having super bad pains in my stomach I literally cry because I'm so stressed out. My husband helps me with our son with timeout and taking his things away but my son laughs and smacks him or me he kicked me in my stomach he'll start smacking himself. I just don't know what to do anymore. I need some advice please.