according to your description the possibilities are,
-as you had intercourse immediately after completion of period and as you are having regular periods there is less chance for ovulation around that period and also pregnancy
possibly your spotting could be ovulatory bleeding,
in that case at present your symptoms could be premenstrual symptoms,
so probably you will get periods soon wait for one more week, if not consult gynecologist and go for blood test
for pregnancy once.