Learn Russian: Вчера я был болен и чувствовал себя плохо.

In Russian, the verb чувствовать (to feel) requires the reflexive pronoun себя (oneself) when you are talking about your own physical or emotional state. Literally, you are saying 'I felt myself badly.'

What case is себя in this sentence?

It is in the Accusative case. Here, it acts as the direct object of the verb чувствовал. The word себя looks the same in both the Accusative and Genitive cases.

Why use the word болен instead of the normal adjective больной?

болен is a 'short adjective'. In Russian, short adjectives are often used to describe temporary states or conditions rather than permanent traits. Since the speaker was just sick yesterday, the temporary short form is perfect here.

How do we know the speaker of this sentence is male, and how would a woman say it?

We know the speaker is male because the past tense verbs был and чувствовал, as well as the short adjective болен, are all in the masculine form. A woman would say: Вчера я была больна и чувствовала себя плохо.

Why does the sentence use плохо instead of the adjective плохой?