Lost temper

My LO has been really challenging lately and having extreme meltdowns. He come home from his Nana’s yesterday and I had a really busy hectic day in work and he was just screaming about everything, he asked for something I give it to him then he would scream no, he was throwing himself on the floor. He broke his drinking cup. He was like the exorcist. I was so exhausted from the day I just snapped and screamed at him ‘what do you want?!’. Afterwards I burst in to tears and hugged him and said I am so sorry and we sat on the sofa for a cuddle but I feel the worst mum in the world today. I can’t stop thinking about it. Please tell me I’m not alone in this. How do we keep our cool in these situations. I don’t want it to happen again.