A 15-day delay in your period can follow from the stress, anxiety and poor sleep you're describing, and a major surgery like a
kidney removal in December can also unsettle your hormonal cycle for a few months afterward. If there's any chance of pregnancy, a home urine test is worth doing first to rule that out.
Next Steps
If the test is negative and your period still hasn't started in another week or two, please see a gynaecologist for a check and possibly a hormone blood test. Working on your sleep and anxiety can also help your cycle settle.
Health Tips
See a doctor sooner if you get heavy bleeding, severe abdominal pain, fever, or start feeling unusually unwell.