I'm 6 weeks 3 days and my symptoms started before I even knew I was pregnant, although they were hardly noticeable. I usually have sore boobs from O until a couple of days before AF, but the cycle I got pregnant on, the pain in my boobs didn't let up at all - in fact, it graduated to the sides rather than the front and it's been like that (increasing in intensity) ever since. Got a BFP the day AF should have come. Started feeling cramps and extreme exhaustion almost straight away. Started feeling hungry-sick on and off, especially in the morning, by about 5 weeks and for the last three days it has been just horrendous - constant nausea and bloating - so I'd say 6 weeks marked the time where it really revved up for me. I am no longer hungry-sick ... in fact, I am no longer hungry at all, just sick. Yuck!
I had a MMC too back in 2005, and I had really bad morning sickness then, so I don't think strong symptoms necessarily always indicate a healthy pregnancy and I wouldn't worry about not having many strong symptoms yet - I don't think it really makes much difference as I've spoken to loads of women on here who never felt anything at all and had perfectly healthy babies. You're also only just pregnant - your baby's only been implanted for the shortest time, so there's plenty of time still to enjoy not feeling like sh*t before the evil hormones start invading everywhere! I've just been noting down progressive changes in my body (mainly in my boobs - I recently developed those little white Montgomery's Thingamies) and hoping they are signs that something is happening, hormones are increasing, etc. What you describe yourself as having sounds 100% normal to me. Not worrying though is easier said than done, I know.
Good luck!