asa no kaigityuu, nemuke wo kanzinagara akubi wo sinai you ni site ita.

Yes:

• 朝の会議中 = during the morning meeting
• 眠気を感じながら = while feeling sleepy / while feeling drowsy
• あくびをしないようにしていた = was trying not to yawn

So the sentence is structured like:

During the morning meeting, while feeling sleepy, [someone] was trying not to yawn.

Here, の links one noun to another.

• 朝 = morning
• 会議 = meeting
• 朝の会議 = morning meeting

So の is functioning like the English idea of of or an attributive link, but in natural English we usually just say morning meeting.

中 after a noun often means in the middle of, during, or while engaged in something.

So:

• 会議中 = during the meeting / in the middle of the meeting

This is a very common pattern:

• 授業中 = during class
• 仕事中 = while working
• 食事中 = during a meal

So 朝の会議中 means during the morning meeting, not just in the morning.

眠気 is a noun meaning sleepiness or drowsiness.

• 眠い = sleepy
• 眠気 = sleepiness / drowsiness

The verb 感じる often takes a noun as its object, so 眠気を感じる is a very natural expression meaning to feel sleepy or more literally to feel drowsiness.

So this phrasing is natural Japanese:

• 眠気を感じる = feel sleepy

Because 眠気 is the direct object of 感じる.

• 感じる = to feel
• 眠気を感じる = to feel drowsiness

Then ながら attaches to the verb stem:

• 感じる → 感じ
• 感じながら = while feeling

So 眠気を感じながら means while feeling sleepy.

ながら means while doing and usually connects two actions or states that happen at the same time, with the same subject.

Here:

• 眠気を感じながら = while feeling sleepy
• あくびをしないようにしていた = was trying not to yawn

So the same person is both:

1. feeling sleepy, and
2. trying not to yawn

A key point: the ながら part is usually the background action or state, and the later clause is the main action.

Yes. あくび is a noun meaning yawn, and あくびをする is the standard verb expression meaning to yawn.

So:

• あくびをする = to yawn
• あくびをした = yawned
• あくびをしない = not yawn

This is very natural Japanese.

It means was trying not to yawn or was making an effort not to yawn.

This does not simply mean did not yawn. It emphasizes conscious effort.

So the nuance is something like:

• I was holding back my yawns
• I was trying not to yawn
• I was making sure not to yawn

The pattern verb-negative + ようにする means:

• to try not to do something
• to make an effort not to do something
• to make sure not to do something

So:

• あくびをしないようにする = to try not to yawn

This is a very common pattern:

• 忘れないようにする = try not to forget
• 遅れないようにする = try not to be late
• 食べすぎないようにする = try not to eat too much

In this sentence, it shows deliberate self-control.

していた shows an ongoing action or effort in the past.

So:

• しないようにした = tried not to yawn / made an effort not to yawn
• しないようにしていた = was trying not to yawn / had been making an effort not to yawn

In this sentence, していた fits the scene well because the person was in the middle of the meeting, feeling sleepy, and continuously trying to suppress a yawn.

It gives a more vivid in-progress past feeling.

あくびをしなかった only tells you the result:

• did not yawn

But あくびをしないようにしていた tells you about the effort:

• was trying not to yawn

So the difference is:

• あくびをしなかった = simple fact
• あくびをしないようにしていた = conscious restraint

The sentence chooses the second form because it focuses on the struggle, not just the outcome.

The subject is omitted, which is very normal in Japanese.

Depending on context, it could be:

• I
• he
• she
• they

Japanese often leaves out the subject when it is understood from context. So without more context, you should not assume it must be I, even though that is often a natural translation in English.

Japanese often puts time and setting information near the start of the sentence.

So 朝の会議中 sets the scene first:

• During the morning meeting...

Then the sentence describes what was happening in that setting.

This is very natural Japanese word order:

1. time / setting
2. accompanying action or state
3. main action

So the sentence flows like: During the morning meeting, while feeling sleepy, [someone] was trying not to yawn.