Problem with my code slowing down and crashing

[SuchUmami]

I've wrote some code that fetches market data from a crypto exchange and then processes it in house. When I first start running it, it's absolutely fine but after several hours it slows down my whole system and then crashes.

Here is a screenshot of the error I get back when it crashes: https://imgur.com/fRTs885

It happens on both my desktop and laptop. Once I stop it and restart my computer, it runs fine again.

Any ideas of what this could be?

[Gribouillis]

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