Sorry if this sounds harsh!
Disclaimer: I'm in my late 30s and I have a two year old and know all too well the challenges that some days - and nights! - bring....and who would like a second soon-ish (fertility issues allowing!)
BUT I am constantly genuinely surprised by how many female friends and acquaintances who are clearly finding their only toddler a real challenge (sleep, behaviour, allergies, general chaos in daily life etc) and/or have PND and/or are clearly frustrated (judging by their real life and FB comments) with either being a SAHM or combining work with motherhood still get pregnant when their current, only child is still around a year old. Two under 2 is notoriously hard. Would it not be better to leave it a bit longer for your own mental health?