Hallow Dear,
Pull out method is not a reliable
contraceptive method. Before ejaculation, pre-ejaculatory secretions (pre-cum) are deposited in vagina unknowingly. Precum does contain some sperms which can cause
pregnancy.
However, even 2 weeks after missing a period if your pregnancy test is negative, it is most unlikely that you are pregnant as these tests are reliable after about a week of missed period.
For confirmation, you may opt for one or both of the following:
1. Beta hCG test on your blood.
2.
Ultrasonography.
Both these tests give reliable confirmation of pregnancy 2 weeks after missing a period.
If your non-pregnant state is confirmed, you may take some progestational preparation like Deviry for 5 days with your Gynaecologist's opinion. 4-7 days after that you will get withdrawal bleeding.
Delayed menses do give rise to soreness in the nipples at times due to high hormone levels in the blood.
Low back pain and heart burn may not be attributed to pregnancy. Some antacid will relieve you from the
heartburn.
I hope this helps you.
Dr. Nishikant Shrotri