6 months PP hormones all wacky- exclusively pumping

Hey guys,

I am 6 months PP , almost 7 months and I just had my first period last weekend(very short and lighter than my previous pre pregnancy periods) and my period ended and ever since I’ve just had intense mood swings and just feel like I’m super sad I want to cry and then days I’m feeling super happy and just all over the place. Wondering if at 6 months something hormonal happens? This just feels like really bad PMSing and it sucks. I could just bawl my eyes out any moment. I am still exclusively pumping and have been from day 1 and could this play a role. Nothing has changed though, I always pump every 6-7 hours. Anyone relate? TIA!