Feeling weird this month

Ashlea • 27 years old... Married the love of my life 5.20.15 and gained 3 amazing step kids, baby #1 due May 2017
So, I stopped trying this month and by that I mean I wasn't being crazy ocd about keeping track of everything and using my OPKs and making sure to bd every other day like I had been. According to the app I ovulated the 1st but I had cramping around the 30th so I'm pretty sure that is actually when I ovulated, regardless I bded both days. Well now I'm either 6 or 8 dpo and for the past 3 days I've been exhausted, taking 2-3 hour naps around 5:30 every night, feeling almost constipated, have had slight cramps and have been excessively thirsty, like I normally drink 1-2 bottle of water in a 6 hour period and have been drinking 4-5, and I've been waking up nauseous but it goes away if I eat something. I feel like I'm not going to end up being pregnant and that if I would be it's too early for symptoms. I don't know, anyone go through anything similar? Any ideas what could be going on with me?