Can you make yourself miscarry or is it something that happens naturally and is out of your control?

Right so this is probably ridiculous but here goes.

First month TTC but I genuinely believed I was pregnant. (Fell first month with DD and second month with DS).

Anyway, I hadn’t had a confirmed pregnancy test as I was 10DPO but I had all the positive symptoms which I don’t usually get before AF.

I had sex the day 11DPO and was due on two days later. However, I come on heavy the next day. (A day early which NEVER happens! Last month I had a 30 day cycle and this month because I was early, it was 27?).

I was only on for 3 days before it turned to brown (old) blood which I no longer counted as being ‘on’.

So I guess my question is was it just a coincidence that I come on early the next day?

Or did I do something awful and maybe caused some sort of awful early miscarriage?