Can lack of appetite be considered an early pregnancy symptom? also, would you be able to start noticing symptoms before you miss your period?

I would not consider it one, although individuals may vary in their symptom pattern. The hormones that trigger the symptoms of pregnancy usually appear at or after the point you miss a period. They are rarely at a level to do so before then.

Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.