Welcome kane, but sorry that you find yourself here and sorry to hear of your losses. The late loss of your son must have been particularly painful 
If it was uNK that was tested, then try to get your actual percentage. The boundary for what is classed as high varies between clinics. At the Coventry implantation clinic (where many of us have had success), anything over 5% is high, and treated with steroids. At other clinics, the threshold is higher so if you were in that middle ground it might be worth getting a second opinion. I've had 5mcs, the last two were very early at 4+2 and 4+5. I was diagnosed with high uNK by coventry (7.9%), and I'm now pg, 20+4 having taken steroids, clexane and progesterone, all prescribed by coventry for the first trimester, as well as metfolin (instead of folic acid - self prescribed!).
Coventry use clexane for its cytoprotective effect on the placenta (stops the placental cells dying), rather than its anti clotting qualities, but it's not normally started until a location scan at around 5 to 6 weeks, so whilst some people really feel that's what makes the difference for them, that might be a bit late for you. I have no idea what effect it would have taken earlier, but perhaps worth a try. Make sure you are scanned at the earliest opportunity to ensure the pg is in the right place though, as blood thinners and ectopics are not a good combination.
The other thing I might suggest to get your cycles back on track is acupuncture. As someone with a scientific background, I was a total cynic until I tried it after my third mc, but it really sorted me out. A lot of people have found it helped to get their periods more normal again, as well as for stress / anxiety. I go to a community clinic, where its a short appointment and they treat two people at once (in separate rooms! ), which made it much more affordable (£15 a session). Other people who didn't get on with acupuncture found reflexology was similarly helpful.
Some recent research suggests that aspirin may do more harm than good in the absence of any clotting disorder, but the jury it totally out on that one, and some people here are taking it and others not. Not trying to scare you, as many people have had success on it, but something to do your own research on.
That's probably way overloaded you already, so I'll shut up now, but please feel free to ask any other questions, or if you just need a bit of hand holding for trying again, we are here.