Como dizer "estou com medo" em inglês

Lembrando que uso de I'm afraid também pode ser utilizado no sentido de receio.

Veja:

Bob: Could you drop these papers at Max's house?

Doug: I'm afraid I won't have time enough. I'm overbusy.

Jack: Are you coming to our meeting at Sunsara's house?

I'm afraid the kids will keep me away from that.

Temos também: to be frightened

Ex: She was too frightened to tell them what happened.

Falando em expressões idiomáticas, acredito que já ouvi to be scared to the bone

Alguém confirma?

sh*t your pants: borrar as calças

Sh*t your pants: borrar as calças.

You scared the hell out of me. And You scared the crap out of me.; You scared the dickens out of me.; You scared the devil out of me.; You scared me out of my wits.; You scared the pants off (of) me.

Ex:

He scared the hell out of all of us.
She really scared the pants off of me.

Fonte: http://idioms.thefreedictionary.com/You ... +out+of+me

I'm afraid of bats = I'm scared of bats = I fear bats = Tenho medo de morcegos
I'm afraid to fly = I'm scared to fly = I fear flying = Tenho medo de voar

I'm afraid I can't stay = I fear I can't stay = Lamento que não posso ficar
I'm scared I can't stay = errado

Monsters scare me = Monstros me assustam
Monsters fear me = Monstros me temem
Monsters afraid me = errado

Sugestões:

I am afraid.
I am scared.

Bons estudos!

Estou com medo:
"I'm scared to death."

Another thing I find interesting and has got to do with the "being/getting scared business" is the following:
Ele quase me matou de susto:
"You gave me such a start." this being from a film called "Master and Commander"...nice film!

Cheerio.

Mais uma:

To dread
To feel very worried about something that might happen or something that is going to happen
She dreads going to the dentist.
Politicians are dreading that voters will lose faith in the President.
We had the visit from the police that all parents dread.
I dread the day she finds out.

Macmillan

Desculpem o conteúdo, mas... Já que existe, é melhor que a gente saiba:

Piss/sh*t your pants (offensive)
To suddenly feel very frightened
I sh*t my pants when all the lights went out.
(Cambridge Dictionary)

Similar ao nosso "tô me c*gando de medo", não é?

If you want to emphasize, you can say:

scared to death
or
I'm scared stiff

For example:
I'm scared stiff of having the operation. (Macmillan Dictionary)
A man jumped out from behind the brick wall and pointed a gun at my head. I couldn't run. I was scared stiff! (Urban Dictionary)

Good idea eduardoad
to start = to give a sudden, involuntary jerk, jump, or twitch, as from a shock of surprise, alarm, or pain:
The sudden clap of thunder caused everyone to start.
start = A startled reaction or movement

Tim