Welcome to HCM,
After going through your history you have Diabetes
and High Cholesterol
and taking regularly Oral contraceptive
Regarding delay in taking tablet as you have taken tablet only 3-4 hours delay hence you are still protected as it is safe up to 12 hours delay.It is recommended if delay is more than 12 hours to use condom for protection.
You should continue to take tablets at regular interval to have optimum protection.
A word of caution as you are diabetic and Cholesterol issues please take care and discuss with your Gynaecologist and keep your blood sugar and cholesterol well controlled.
Please practice safe sex
as it not only protects from unwanted pregnancy
also protects from STDs.
Please take care