I can understand your concern.
After about one week of your missed periods you can undertake a urine pregnancy test.
There are many kits available in the market like preganews, i can, velocit, etc. You can use any. They all work on the same principle.
And yes they are pretty accurate.
Also you can get a ultrasound and that will also be helpful.
Kindly consult a gynecologist for further management. Best regards.
Dr. Anil kumar jain.