Yo me fui cansando un poco en la grada, pero no quería perderme el final.

Yes. In Spanish, subject pronouns are often omitted because the verb ending already shows who the subject is. So Yo me fui cansando... could also be simply Me fui cansando...

Here, yo is probably included for emphasis, contrast, or a slightly more personal tone. For example, it can suggest something like:

• As for me, I was getting a bit tired...
• I myself was starting to get tired...

It is not required grammatically, but it is perfectly natural.

Me fui cansando uses the structure irse + gerundio. This often expresses a gradual change over time.

So me fui cansando means:

• I gradually got tired
• I started to feel more and more tired
• I was getting tired little by little

It is not the same as simply me cansé, which usually means I got tired or I became tired as a more complete event.
With me fui cansando, the sentence highlights the process.

Yes, ir normally means to go, but in some verbal structures it has a more grammatical function rather than a literal movement meaning.

In irse + gerundio, ir(se) helps express that something happens progressively or step by step.

Examples:

• Me fui acostumbrando = I gradually got used to it
• La gente se fue yendo = People gradually left
• Se fue haciendo tarde = It gradually got late

So in your sentence, fui is not about physically going somewhere. It helps show the idea of a gradual development.

The me belongs with cansarse, the reflexive form of cansar.

• cansar = to tire someone / to make someone tired
• cansarse = to get tired

So:

• Me cansé = I got tired
• Me fui cansando = I gradually got tired

The me shows that the subject is experiencing the change personally: I got tired rather than something tired me.

Because this is the construction irse + gerundio, and that structure requires a gerund:

• cansando = gerund of cansar
• cansado = past participle / adjective

Compare:

• Me fui cansando = I gradually got tired
• Estaba cansado = I was tired

So cansando focuses on the becoming, while cansado describes the state.

Un poco means a little or a bit.

In this sentence, it softens the statement:

• me fui cansando = I was getting tired
• me fui cansando un poco = I was getting a little tired

It suggests mild tiredness, not extreme exhaustion.

In Spain, la grada commonly refers to the stands, bleachers, or seating area in a stadium, arena, or similar venue.

So en la grada means:

• in the stands
• up in the seating area

This is very natural in Peninsular Spanish, especially in sports or performance contexts.

Quería is the imperfect of querer, while quise is the preterite.

Here, no quería is used because it describes an ongoing mental state / intention in the past:

• pero no quería perderme el final = but I didn’t want to miss the end

The imperfect works well for thoughts, wishes, intentions, and background states.

If you said no quise, it would sound more like:

• I refused to
• I didn’t want to as a more definite, completed decision

So no quería is the more natural choice here.

Perderse algo means to miss something in the sense of not seeing / not experiencing it.

So:

• perder = to lose
• perderse = to miss out on, to miss

Examples:

• Perdí las llaves = I lost the keys
• Me perdí el concierto = I missed the concert

In your sentence:

• no quería perderme el final = I didn’t want to miss the ending

The me does not mean myself in a literal English sense. It is just part of the idiomatic verb perderse algo.

Because the sentence contains two different pronominal/reflexive verb forms:

1. me fui cansando
   Here me goes with cansarse.

2. perderme el final
   Here me goes with perderse algo.

So the two me pronouns are not doing the same job in one big structure. Each belongs to its own verb phrase.

Yes. A simpler version might be:

• Me estaba cansando un poco en la grada, pero no quería perderme el final.
• Me cansé un poco en la grada, pero no quería perderme el final.

But each version has a slightly different nuance:

• me fui cansando = gradual process, little by little
• me estaba cansando = I was getting tired, ongoing process
• me cansé = I got tired, more like a completed change

The original sentence is natural and expressive because it highlights the gradual build-up of tiredness.

It sounds natural and conversational. The speaker is describing a situation in the past:

• they were in the stands,
• they were gradually getting a bit tired,
• but they stayed because they did not want to miss the ending.

The contrast introduced by pero is important:

• I was getting tired...
• but I didn’t want to miss the end.

So the sentence conveys mild discomfort plus determination to stay until the end.