You won't find 'poe-he' in any dictionary. It is one of those verbal expressions that can mean a lot of things - from positive to negative and everything inbetween. Not only does it depend on the context, but also on the tone of voice.

The answer I gave is just an indication of how this could be translated.

I would say this is the same as "hé hé" or "poe poe"...
see (German): https://www.buurtaal.de/blog/hehe-seufzen-niederlaendisch

Während ein einzelnes hè entweder Staunen, Schrecken, Erleichterung, Unverständnis oder Enttäuschung signalisiert, drückt die Doppelform hè hè in erster Linie Zufriedenheit mit einer erbrachten Leistung oder Anstrengung aus
~Something like: while a single hè signals astonishment, horror, relief, uncomprehension or disappointment, the double form hè hè primarily expresses relief over achieving something or completing something strenuous

In this case, the achievement is somewhat sarcastic - and the expression represents the effort it's taken to "achieve" three whole days in three months. In English, I'd just say "phew", "whew", or, in this case, "oof". But it depends on your register and the age of your speakers, of course...

I think this would work.