My Last Regular Period Started On July 26th And Ended

My last regular period started on July 26th and ended July 29th. I ovulated on August 6th and had unprotected sex with my husband on August 2d and 6th. Started cramping on August 9th and started feeling nauseous on August 13th. Then i got what seemed light period with period cramps on august 18th ,the only thing usual with those period was that they were a lot lighter than usual i barely filled a tampon on the first day when I usually go through at least 3 super absorbant ones. As for the next days it was pretty much nothing and more pink red . Took a pregnancy test on august 17 and it came back negative took an other one on august 27 still negative but my nausea just got worst and started having food aversion and gagging on some food smells.im feeling tired Way more than usual and I frequently have very mid period cramps don't know what to do or what to think. I also noticed last week I had a lot of brown discharge for a couple of days. And this week I had a lot a period like cramps and still feeling nauseous and burp a lot thought the day with fluids and been sick once yesterday.