period no cramping! advice needed!

So my period is here super light but still enough to fill a regular tampon one the first day along with another half a tampon on one side the first day deep red blood. Before I even started I had brown spotting. I'm on day 4 only filling half a tampon a day. It's weird I haven't had any camps at all! And usually always get camps! I do have thyroid issues but my levels are all in normal ranges currently. Does anyone have any advice for why this could be happening? Also why do I literally have half a tampon with blood on one side/half of it? And the they is white still? Background me and my boyfriend are ttc and have sex everyday I'm not bleeding with him cumming inside every time. Advice please and thank you! 
Update: I forgot to add my breast are super sore usually are before my period but not during. And today's tampon wasn't even half way full barely anything and day 4/5 usually is my heavier days