If you honestly feel like this please call LifeLine or Beyond Blue and talk to someone - now, tonight.

You can also speak with your GP or OB, whomever is handling your pregnancy and get some information on who can help you.
These are serious things you are saying and you need professional help to deal with them

It is a big thing to admit being terrified, and feeling like you do, so well done for saying it 'out loud', now you need to do something about it.

I am scared to death of having 2. I am having pictures of myself leaving one behind, or forgetting to pick her up from kinder... Flashes of chasing them around supermarkets and having the older one be hideously jealous and tipping baby out the bassinette... Every horror I can imagine and some that are beyond a joke have gone through my head.
It is super scary and I have no idea how I will cope. But I know I have no choice but to cope and will do whatever, talk to whoever, to cope. That one moment when my daughter tells me she loves me makes up for everything and is enough to push through the anxiety.

Give your little one a big cuddle, take a deep breath and do what you have to do to cope, they need you.