A home urine test is quite accurate 1-2 days after your missed period. But if you want 100% confirmation, a beta-hCG blood test on doctor's advice is the gold standard.
No need to overcomplicate, just buy a simple prega-news kit from the local chemist and test with early morning urine. You'll get the result in 2 minutes.
I think testing on the first day of your missed period is the most gentle way to get an accurate result. Early testing can sometimes show a faint line which is confusing.
Testing around 4-5 days after your missed period is ideal for a clear result. Don't forget to keep up with your regular doctor checkups if you have thyroid like me.