Do not overburden yourself. The Prophet ﷺ saw a man standing in the sun who had vowed to stand, not sit or take shade, and to fast; he said: “Command him to speak, to take shade, to sit — and to complete his fast.” (al-Bukhārī). Islam does not want you to torment yourself.
العربية: عن ابن عباس رضي الله عنهما أنّ النبيّ ﷺ رأى رجلًا يقوم في الشمس، فقالوا: نذر أن يقوم ولا يقعد ولا يستظلّ ويصوم، فقال ﷺ: «مُروه فليتكلّم وليستظلّ وليقعد، وليُتمّ صومه». (البخاري).
Worship steadily but don't crush yourself — take rest, shade and ease; Allah does not want your hardship.