Sudden urge for another child after coming off meds

My son is almost 2, and I was diagnosed with PPD right away, i had an extremely traumatic labour and spent 12 weeks in the ICU and my son spent 20 weeks in the NICU, he was full term but we had complications with sepsis and both almost passed, we spent most of our days apart or on a video call but in the first 10 weeks I got to hold him twice so I was put on citalopram 30mg and mirtazapine 15mg within maybe 2 weeks of birth, I’m a single mum so I was on my own from the get go coming home, I decided it was time to come off my meds about 8 weeks ago, and have been completely off Them for about 3 weeks now, during my time on the medication I was adamant I would never have another baby, I hated the thought of it, I didn’t want to be a mum again, but the last 2 weeks I’ve been extremely broody, I want another baby, to the point I’m considering sperm donation, I have no idea why the sudden urge to have a second baby considering I hated the thought so much but I can’t shake it, it’s all I can think about! Wtf is going on?