One way that I use to cope with negative feelings throught the day is to take the negative sentences and then omit the needless words, crystalize them into absolute, almost timeless sentences, like a mathematical proof.

For example, instead of saying:

I have just wasted two hours tonight on doing nothing and watching Youtube

I would frame it to something like:

I watched Youtube for two hours tonight

Which makes the bad feelings more subjective, which (not so concidentally) reminds me of this great Stoic quote: Events were objective, but our opinions about them are not.

Spending two hours on Youtube is not necessarily a good or bad thing. It just was.