I had sex last month on days 6 and 8 of my cycle (used condoms with no issues, but no hormonal birth control). I believe I ovulated on or around day 13, so even if there had been a mishap, the sperm would have needed to hang out for a few days before the egg showed up to the party. Period came on time (usually comes between days 29 and 34 and showed up on day 29, not unusual). Period was a little lighter than usual, though still enough blood to fill a few super tampons in the first few days. Cramps were not as intense as usual (usually killer) but had very bad cramps overnight on the first day of my period. So there was significant bleeding over several days and some definite strong cramps, though my period was milder than usual on both counts. The past week or so, I've been nauseous and the past three days, my chest has been very tight and I've had trouble drawing full breaths. I read that shortness of breath is a fairly common early pregnancy symptom, and the nausea - while it could be partially blamed on mucus drainage from a cold I've had - is worrying, too.
I'm really concerned with the slightly gentler period (though they have been gradually becoming milder over the past few months) and now nausea and shortness of breath that won't go away.
I've also just been very stressed the past month and a half. It's very cold. I've had a mild cold the past week. My boyfriend is sure I'm anemic - there's a family history and I've been feeling fatigued, headachy, short of breath. I've very very rarely felt short of breath for short periods of time (a few hours at a stretch) seemingly randomly in the past but never for most of three days.