No. Whenever you are at risk because of activity, you are only at risk for that menstrual cycle. If your boyfriend touched you and you had a normal period, then you are not pregnant. If he touched you after that and now you're late, I'd raise an eyebrow, but I wouldn't worry.
Nipple soreness can also be a PMS symptom. It doesn't always happen if you are pregnant, it could happen before you have your period as well.
If you have missed your period and are pregnant, you most likely got pregnant around 14 days before your missed period.
no
You could well be.
If she has had her period before, then yes
It is possible, but extremely unlikely.
no
Yes
If you really had a miscarriage, you can't still be pregnant, but you could be pregnant again before you get your next period.
Yes, you could still be pregnant, consult your doctor for a routine examination.
You could be. If you miss your period you should take a pregnancy test.
Anytime you have sex, period or no, you can get pregnant.