Cramping/twinges/a few sharp ones... help!

My s/o and I were intimate all days surrounding ovulation. Two days before my period (which is down to the hour predictable and heavy) I had light brown discharge/spotting and light pink/bright spotting for only about 8 hours (enough to barely cover the tip of a tampon. This stopped one day prior to my period and I had NO period. The thing is, I run on a 28 days cycle - so it's really only been MAXIMUM 21 days, but probably more like 19 IF we conceived.

I haven't taken another pregnancy test yet - waiting until the end of the week.  I've been irritable (a million times worse than PMS), nauseous, smell is heightened like CRAZY, constipated (TMI sorry), and have been having anywhere from dull period like cramps to sharper type pain like when you're ovulating and then twinging type dull pains down my lower abdomen.

You think it's likely that I'm pregnant or no??  And if so, is cramping normal at this stage (3 weeks roughly)?  Should I be concerned for an ectopic pregnancy at all with the rare occasional sharper pains?

Thanks!!!