Could I have had a miscarriage without knowing I was pregnant

So I got my period on the 29th of April and it lasted for a week as per normal. (My partner and I have unprotected sex as I have the implanon the bar in my arm so we don't use a condom) my partner and I do make love a fair bit when I'm not on my period. Anyway. When it ended we had sex that night. And also on the Sunday. Then I started bleeding again. Then it went away again 4 days later it was very light bleeding. But my partner and I had sex this morning and I went to the toilet and it was fine then went again a few hours later and there was what looked like blood clots there was a really big one I didn't realise till I wiped and there was a little bit on the paper so sorry for the details. I'm just scared as I've seen on here what happens to some ladies when they miscarriage. I haven't had any pregnancy symptoms so haven't taken a test I'm just worried! Please help