What do I do if I forgot something?

Question

I've learnt English for many years and have never seen the sentence construction like this (well, now I have):

What do I do if I forgot the appointment with my doctor?

This sentence was taken from a language learning app and I'm learning Spanish, its original sentence is:

¿Qué halgo si olvidé la cita con mi doctora?

Is this just a literal translation from Spanish or it's valid English? However I couldn't understand it yet since I've always been taught that there are "only" 3 conditional forms and 4 if I include the mixed conditional. However, just recently I read a book written by Swan, and it is said there that those so-called conditional types aren't exactly always like that, the writer said that every combination of tenses is possible.

Therefore, could you please explain why is this sentence valid or even makes sense? Someone (a native English speaker) told me that the sentence refers to the two different periods i.e. now and in the past. However, I still don't understand, and why wouldn't it be written like this:

What would I do if I forgot the appointment with my doctor?

Answer 1

In American English,

What do I do if I forgot my doctor’s appointment?

and

What would I do if I forgot my doctor’s appointment?

are both valid, but, among careful writers, mean different things.

The first means

What do I do now, given that I actually did forget my doctor’s appointment?

That sentence has nothing to do with a hypothetical situation. Your friend is correct that the sentence refers to a question in the present arising out of a past fact.

The second sentence means

What would I do under the hypothetical circumstances that I forgot my doctor’s appointment?

It is a conditional statement referring to a potential future. However, I must admit that many American speakers would not make the distinction. American English seems to be creating a new subjunctive out of the conditional. Many would say for the conditional statement

What would I do if I would forget my doctor’s appointment?

The usage disturbs me, but I hear it frequently.