Confused pregnant again or just period starting

I had my first baby 3 months ago. My Husband and I had sex in the beginning of February. We didn’t use protection but afterwards I used a plan b pill. About 2 weeks after that I get my iud put in. They gave me a pregnancy test before putting in the iud but I doubt the HCG hormones would be anything at that time. Now tho I’ve been feeling nauseous, getting headaches, ringing in my ear, some dizziness but not much, feeling the need to pee more often then I did, and really hard cramps (almost as bad as my labor pains). I don’t remember if I ever got nauseous or had to pee more often, before I got pregnant, when I was getting my period. I’m thinking about getting a pregnancy test tomorrow just to see but I wanted to know y’all’s opinion. Thank you in advance!