I felt exactly the same as you, had a mmc at 10 weeks in December. Currently pregnant again and am 12+2, we had our 12 week scan yesterday.
I'd had 3 scans previous to that, because I was just so worried and anxious all the time. I did have a couple of bleeds and some funny discharge so they were for peace of mind really. DH was very supportive and aware that me being stressed and worried isn't good for me or the baby.
Do you have a date for your 12 week scan? I have found that it was such a huge milestone and despite having the scans before this one it's the one which seems to have (for now at least) settled my anxiety quite a bit.
I was exactly the same with symptoms, I felt like death up until a week or so ago and thought that was great as it made me feel like this baby is a fighter. Then they started to come and go and just like you I would panic when I felt well!
Your DH is right that having a scan won't stop you miscarrying, but it will reassure you, and once you've seen a strong heartbeat the chances of mc reduce drastically. Having said that, you must be due your 12 week scan soon, so maybe as you've made it this far, you can wait a few extra days?
Have you seen the staying positive after miscarriage thread? A lovely bunch of ladies, all in the same boat but at different stages of pregnancy, so really helpful with information and positive vibes!:
www.mumsnet.com/Talk/pregnancy/2833968-Staying-posifrickentive-Thread-14-for-ladies-pg-after-mc?