Question: If something unexpected (and incredibly unlikely) happens, should we take it as something deeper or just a fact of life?

Something highly unlikely and very positive happened at a very bad and negative point in my life, this event arguably showed a very different future to the one I imagined.

Don't know how to read into it, or how my actions should be after the event, should I embrace the change?

Answer: 
Nothing happens for a reason. Reason is something given by us. 
Everything except Nibbana happens & happens due to causes. Nibbana doesn't happen, it is existent. Thus not caused.
In the [Sivaka Sutta (SN36.21)](https://www.accesstoinsight.org/tipitaka/sn/sn36/sn36.021.than.html), the Buddha explains that not all experiences are caused by kamma. Sometimes, it's just the weather or something else that's not extraordinarily significant. Not everything happens for a reason.

> 
> As he was sitting there, he said to the Blessed One, "Master Gotama,
>  there are some brahmans & contemplatives who are of this doctrine,
>  this view: Whatever an individual feels — pleasure, pain,
>  neither-pleasure-nor-pain — is entirely caused by what was done
>  before. Now what does Master Gotama say to that?"
> 
> 
> [The Buddha:] "There are cases where some feelings arise based on
>  bile. You yourself should know how some feelings arise based on
>  bile. Even the world is agreed on how some feelings arise based on
>  bile. So any brahmans & contemplatives who are of the doctrine & view
>  that whatever an individual feels — pleasure, pain,
>  neither-pleasure-nor-pain — is entirely caused by what was done before
>  — slip past what they themselves know, slip past what is agreed on by
>  the world. Therefore I say that those brahmans & contemplatives are
>  wrong."
> 
> 
> "There are cases where some feelings arise based on phlegm... based on
>  internal winds... based on a combination of bodily humors... from the
>  change of the seasons... from uneven care of the body... from harsh
>  treatment... from the result of kamma. You yourself should know how
>  some feelings arise from the result of kamma. Even the world is agreed
>  on how some feelings arise from the result of kamma. So any brahmans &
>  contemplatives who are of the doctrine & view that whatever an
>  individual feels — pleasure, pain, neither pleasure-nor-pain — is
>  entirely caused by what was done before — slip past what they
>  themselves know, slip past what is agreed on by the world. Therefore I
>  say that those brahmans & contemplatives are wrong."
> 
> 
>