It gets heavy -- an idiom?

Hi, can you please tell me if the phrase ‘it gets heavy’ is an idiom? I mean, the phrase means that something becomes difficult rather than heavy, doesn’t it?[YSaerTTEW443543]

TOEFL listening discussions: Two roommates talking about fraternities[YSaerTTEW443543]

Hi Torsten. Well, ‘it gets heavy’ is not an idiomatic phrase. ‘Heavy’ has several meanings, including slang (a. unpleasant or tedious / b. wonderful) so I really need to see the context.

Hi Charles, the context be these lyrics for example:

Fallin Down"

Sometimes I don’t wanna wake up alone
But sometimes I wanna wake up and be on my own
Sometimes I don’t wanna walk by your smile
But at the same time I don’t wanna let people down

Can you imagine, the weight of a world
Placed on your shoulders, trapped in this world
And no-one can reach you, ohhh ohhh ohhh ohhh
So no-one can help you, nowwwww

It’s getting heavy I think I’m bout ready to break down
I’m standing up, but I’m fallin down
Time keeps on tickin on wish there was a way to slow it down
Someone pick me up, cause I’m fallin down
I’m fallin down, down, down, down,
Down, down, down, down
I’m fallin down, down, down, down,
Down, down, down, down

Why is it so easy for you to blame
I’m only human we’re all the same
I’ve given up everything in exchange for being alone
I’m shaking these demons underneath all the pride, ohhhhhhhh

Can you imagine, the weight of a world
Placed on your shoulders, trapped in this world
And no-one can reach you, ohhh ohhh ohhh ohhh
So no-one can help you, nowwwww

It’s getting heavy I think I’m bout ready to break down
I’m standing up, but I’m fallin down
Time keeps on tickin on wish there was a way to slow it down
Someone pick me up, cause I’m fallin down
I’m fallin down, down, down, down,
Down, down, down, down
I’m fallin down, down, down, down,
Down, down, down, down
I’m fallin down, down, down, down,
Down, down, down, down
I’m fallin down, down, down, down,
Down, down, down, down

It’s getting heavy I think I’m bout ready to break down
I’m standing up, but I’m fallin down
Time keeps on tickin on wish there was a way to slow it down
Someone pick me up, cause I’m fallin down

TOEFL listening discussions: A conversation between two students (1)

Well, it’s always hard to interpret the haziness of song lyrics, but:

…the weight of a world
Placed on your shoulders
…Time keeps on tickin’ on wish there was a way to slow it down

I suppose ‘it’s heavy’ refers to his weltschmerz…or maybe just his social responsibilities? So either ‘serious’ or ‘a. unpleasant or tedious’.