A
beta hCG under 0.1 together with four negative home tests means pregnancy is essentially ruled out here. A delayed period for a few weeks after taking the emergency contraceptive pill is common, since it temporarily disturbs your normal hormone cycle.
Next Steps
If your period doesn't start within another week or two, a pelvic ultrasound and
thyroid test can check for other causes. Whether to take a tablet to bring on your period, and which one, is best decided by your gynaecologist after a quick review.
Health Tips
Please see a gynaecologist sooner if you develop pelvic pain or unusual bleeding before your period returns.