Sometimes you can at the second round of ultrasounds (bout 18-20wks) but there are no guarantees that the baby will be in the right position to see or whether what the ultrasound person says is correct - it just a good educated guess.
At the first ultrasound sometimes but generally around 20 weeks
With a sonogram:
At 24 weeks almost always,
at 18 weeks, only if you're lucky. With amniocentesis at about 12 weeks (but higher risk).
Most Dr perform an ultrasound around the 16 to 22 weeks point in pregnancy where you can ask the sex of the baby.
Gender can be determined by ultrasound as early as 12 weeks in some cases. Most people are not that lucky. Most find out by elective ultrasound around the 20th week of pregnancy.
No the pregnancy test lone will not tell you the sex of the baby.
Don't make sex
No, but a pregnancy test can.
No, sex is fine during pregnancy. If you have a sensitive pregnancy the doctor would tell you to abstain.
No, but a pregnancy test can.
Go buy a pregnancy test and take it.
Yes, all the symptons you say you have are the early stage of pregnancy.
some women have "dreams" that let them know about their pregnancy
It varys from woman to woman but most Dr's will perform an ultrasound around 20 weeks of pregnancy.
Pregnancy is usually not obvious at this stage. If you mean can medical people tell, then yes, they can tell from about three weeks.
You can tell the sex of the woman at any time (female), but the sex of the baby can be determined usually around 16-20 weeks into the pregnancy, or 4-5 months.
The only way to know for sure is through an ultrasound.