Reliable Rhyme

Just in case you're feeling the strain
Here's a poem to relive the pain
Although the time costs me dear
I know it brings a smile and cheer

There must be some words that could sound right
But alas from my mind they have taken flight
So read my words which at least do rhyme
Imagine it to be a sonnet, which at least is mine

So as I struggle with the last verse of three
You can tell that the day has got the better of me
Because these lines have less of a punch
Perhaps I should have gone to the pub for lunch!