Hell hath no fury like a 2 year old

I love my son. He's doing a great job at being two, but the screaming, the biting, the tantrums, the time outs ... and I'm just talking about me here. Seriously, 2 is really hard. I keep consoling myself with the thought that not all of my parenting will be contained in just one year. I get 18 years to raise him. It's just so hard. I read everything I can get my hands on. I take classes. I consult friends/family, and I pray often. It's got to be the most challenging, humiliating, humbling, and exacerbating experience of my life. Half the time I feel like I'm going nuts, and the other half I'm so proud. I wonder if there is something wrong with me, and then I wonder if there is something wrong with him. I love my astrology book- I looked up his sign ... it recommended getting a super strong playpen when he was born and then staying inside it until he was three. We had to go to the emergency room one night because he had a tantrum and wacked his head on his bed frame. He hit his head so hard - he had a bump, he threw up, he was tired, SO off we went to the ER. The doctor was hugely sympathetic. She put her arm around me and asked me if I was ok.
I sobbed.
She said "they are absolutely demonic sometimes." She assured me it was normal, and that I was a good mom.
I hope she wasn't lying.