Stomach Tightness, Smell and Lower Back Pain (Important)

Me and my boyfriend have been ttc for over 7months now and just this month things have seemed a little bit off, but my calendar said I just stopped ovulating. My last period was also lighter then my usual periods.

But the last like two-three times we have had sex and he's ejaculated inside me ive been getting a really tight discomfort in my stomach to the point I have to sit or lie down or at least bend over to be comfortable and I start to feel bloated.

Also just yesterday for the first time I walked into a room we had been using the same air freshener in for a while and the smell was so overwhelming that I had to walk out before I puked and that happened again after coming home to the food that was cooked.

And last but not least in the last two-three days of not more (I haven't been counting), I've been getting this really horrible lower back pain that only happens in the morning and late afternoon from what I can tell so far. But it hurts to the point that its debilitating, and its only in my lower sometimes traveling to the middle of my back.

I was curious if anyone else has every delt with this and could possibly know what it is?