I'm from eastern europe too, I feel like I almost died from the august 2020 heat, this year I couldn't belive my eyes seeing 37°C on the weather app last week(and continues to rise). The hail mary was fans for me, but air conditioning is something that will get harder to live without as years roll by and the temperature increases. I know I'm not the intended audience, but what worked for me was spending more time in rooms where the sun doesn't hit as much(for me it's the bathroom), standing near walls(I noticed they don't catch a lot of heat and they are not too cold to lean on), every few hours try to splash some water on your face and neck and maybe(I don't know if this works, didn't try it) towels that are wet and were left a bit in the fridge(I'd avise much caution with temperature change to avoid termic shock, for the towel too not be too cold and the body too warm). Hydrate and avoid going outside mid day as much as possible. Summer gets easier when you work in an air conditioned office, but until then, good luck and drink water.