I am so sorry for your loss, lucy 
Any pregnancy loss is upsetting, but early losses like yours (and mine) are so common and don't really mean anything about your future fertility that it is important that you grieve, and then move forward from it.
I had 4 MMCs, all before or around the 12 weeks mark.
Here is what helped me, please feel free to pick and chose what chimes with you and completely ignore what you don't find helpful - i know that everybody deals with their grief differently.
- MC is common. Whenever I found myself asking 'why me?', the obvious answer was 'well, why NOT you?'. It happens to healthy woman who do everything right all the time. There are estimates that up to 1/3 of fertilised eggs don't lead to a live baby.
- Many early MCs are the result of a problem with the pregnancy, be it a chromosomal abnormality or an issue with the placenta or whatever. It helped me to consider that maybe nature had good reasons to not let this pregnancy progress beyond a certain stage.
- You have proven that you can get pregnant! This is good - failure to conceive is soul destroying (I hate even the term). You have been pregnant once, you can become pregnant again.
- What you are grieving is the loss of the baby you were hoping to meet and that you had already invested love and care and protectiveness in to. What you actually lost was a pregnancy, not a viable baby, but the possibility of a baby, not yet the fully formed real thing. I found it comforting to think of my lost pregnancies, not lost babies. I know this is offensive to some women who had MCs and I hope this idea does not upset you further - I'm describing what helped me through it.
- I never wanted anybody else's baby, I wanted mine which is why dealing with pregnant mothers at work, or young babies, was not that upsetting. It reminded me that people were having babies all around me, all the time, so why not me one day? (See 'why me?''why not me?' above - it's all about how you frame it!)
So, grieve, cry, eat chocolate, curl up and hide away for a bit, then take a deep breath, go for a walk and face the world again. Since the beginning of time women have had to make the leap of faith that is embarking on conception/pregnancy/labour/child birth/raising offspring and it is all fraught with risk and can be quite scary. But it is also the single most rewarding, exiting and enriching experience of my life. And yes, I also had successful pregnancies, so why not you?!
Look after yourself, and wishing you very best of luck 