Hi,
Proteins in your diet should not affect the
pregnancy test. Since all the three pregnancy tests you performed week after a week of missed period, you cannot be pregnant. After a week of missed period, the results of these tests are reliable. Still if you are suspicious and want to confirm the pregnancy status, you may perform
Beta hCG test on your blood. Values more than 25 mIU/ml are diagnostic of pregnancy while in non-pregnant state, the values remain under 5 mIU/ml.
To get the menses after missed period in non-pregnant state, you may take some Progestational product like
Deviry (with an advice from your Gynaecologist), then within 4 to 7 days, you would get withdrawal bleeding.
Occasionally, periods may get delayed even without pregnancy - due to transient
hormonal disturbance or physical or mental
stress. If such irregularity persists, please report to your gynecologist.
I hope this resolves your issue. Let me know if I can assist you further.
Regards,
Dr. Nishikant Shrotri