3 months postpartum - what’s going on???

WARNING: Long post ahead……I couldn’t find a section specifically about postpartum, but anyone else experiencing early pregnancy symptoms 3 months PP but NOT PREGNANT?????? any advice, suggestions, or sharing of personal experience is welcome.

Some background - I’m 12.5 weeks PP. I EBF, but my son does take a pacifier, eats anywhere between every 2 - 5 hours during the day (I know that’s a long time but if he’s sleeping or just up and happy I don’t see a need to force him to eat.) and even though he’s currently going through a sleep regression….he was sleeping a solid 6-7 hours for the first stretch of the night. All this to say - I understand my cycle is more likely to resume at any point with this feeding schedule

Also - pre-pregnancy, period symptoms were nothing too painful, but I could always tell what was going on in my body. I could feel ovulation symptoms…then I would be good until a couple weeks later when cramping would start and soreness in my back and chest and there was this very distinct feeling in my body that told me my period was a day or two away - however, those were the same symptoms as my early pregnancies (3 pregnancies, but only have 1 baby with me, so this is my first time experiencing postpartum)

ANYWAYS, at around 8.5 weeks PP I felt like my period was coming back - a lot of cramping, discomfort, and fatigue…. It got worse and then stopped after a few days I even told my friend who got hers back 8week PP while EBF and she told me it was a possibility….but a few days later still nothing. Then about a two weeks ago (around 11 weeks PP) it started again and this time I got that distinct feeling. I told myself maybe the previous cramping had been ovulation? There was brown spotting when I wiped on that Tuesday afternoon , it was less or non existent on Wednesday, and then on Thursday it was a little heavier and brown and turned pink by the end of the night……I thought Friday my period would arrive but no….nothing. Clear cervical mucus instead?????
I had cramping for a few more days and then it was gone around Christmas Eve.

Now I’ve had slight cramps in my lower abdomen, back ache, sore chest (nursing my lil guy is uncomfortable), bloating, suddenly extremely emotional to the point that my husband noticed and has been asking if I’m ok, and the nausea is getting worse by the day! -Two days ago I gagged at a poopy diaper, and yesterday it was just lingering all day……..
I tested to make sure it wasn’t my worst fear of Irish twins….but the two test said negative (one clear blue digital early detection and one Walgreens early detection)…….if that was implantation bleeding wouldn’t a BFP show up by now being that ovulation would have been weeks ago? If it’s not pregnancy why didn’t my cycle come? Why am I suddenly so nauseous after all the period like/early pregnancy symptoms if I’m not pregnant?
I would let it all go if I hadn’t started spotting only for my period to not show and if it weren’t for the recent nausea……..is it just my hormones giving one last big dip before finally leveling out?
Anyone got any ideas of what this could be????

And the other thing is…..does it matter if I AM pregnant? Is just going with the flow of life for the next couple of months until I inevitably discover it soooooooo bad? I feel like it is because of how close together my pregnancies would be it could be a problem, but if the test are showing negative, how far should I go to figure this one out?
Thoughts?