Does anyone have an explanation for this?

Has anyone experienced this or has an explanation?

July I lost my virginity I had sex that time only that month my period and symptoms were as usual.

The first month I noticed the change was September. I had symptoms that I’ve never experienced before like bubbly stomach, tender breast and swollen ankles together etc with regular pms symptoms I usually experienced and my period came 5 days late and it’s never late. I haven’t had sex since then and my cycle and symptoms were as it usually is.

Then this month November I was sexually active again. Last week I started getting pelvic cramps kinda like when I’m ovulating or pmsing, Lower back pain, fatigue, constant nausea and feeling like I’m gonna faint, bubbly stomach, late last week I had spotting for 2/3 days this is about a week before my period is due and I also experienced other symptoms.