If your periods have been late by 5 days, ideally a urine pregnancy test should be performed on the 7th post missed period day to get reliable results. However if the results have been negative and you still carry a concern then the best way to rule out pregnancy would be to get a serum beta HCG test which if found to be raised levels, then pregnancy is confirmed. On the contrary, if the hcg levels are less than 1, then pregnancy is ruled out.
If the test is negative then you should opt to wait till 15 days post missed periods to allow the menses to resume naturally and if they don't then you may opt for a withdrawal bleed with progesterones to resume your menses.
I hope i have answered your query in detail,
wishing you good health,
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