Help - 11dpo

I am 11 dpo and since lastnight I’ve been burping a lot like what i ate that morning and it’s continuous to where i feel nauseous with it but never actually throw up just like baby barfing in my mouth which is gross (sorry) it’s also a very subtle nausea not like i need to throw up right now it’s weird . I cramped a little here and there lastnight and i feel tightness today and a little pressure and I’ve cramped a few times but not massive cramps like period cramps just like aches if that makes since my period is supposed to be here on the 21st and i got a negative test yesterday morning .... I’ve also been super tired .... what do you ladies think ?