Hi Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern...
Emergency contraceptive pill like I pill prevents pregnancy by inhibiting
implantation of fertilized egg on to uterus. It is 95% successful if taken within 24 hours of having sex. So chances of pregnancy are very less. You have also done a pregnancy test, which rule-out possibility of pregnancy in you.
Delayed period after intake of plan B pill is a common problem. It is known side effect due to high dose of hormone levogesterol contained in the pill. Therefore your period could be delayed for next one or two cycles. The bleeding you had 5 days later is withdrawal bleeding & it occurs commonly after emergency pill intake.
One should never use emergency pill as regular method of
contraception. Use condoms or regular contraceptive pills to prevent pregnancy in future. Frequent intake of emergency contraceptive pills can cause serious problems like
irregular periods, ectopic pregnancy, ovarian hyper-stimulation syndrome & even
infertility.
For more queries,Consult a gynaecologist
Hope this information helps