Wow, Loueyrose that sounds frustrating and perplexing. I've never had a chemical pregnancy.
In my (limited) understanding, spotting can have different causes and it's often not a problem at all. Lots of people have it and have no trouble conceiving. Some online sites who say it is a problem are trying to sell you something.
For example, the bleeding could be from your cervix (eg from a cervical ectropion / erosion). In which case it would have nothing to do with your uterus or uterine lining. I've recently been told I have a cervical ectropion, and this explains some bleeding I had after sex once or twice. I've also had regular luteal phase spotting (around 10 days PO) for at least 15 years. I don't know if they are related, but they could be. I've been TTC for 12+ months and I'm going to start general investigations soonish, now that I can.
I know sometimes people can succeed in addressing the spotting by taking supplements (eg vitex / agnus castus), using Chinese traditional medicine etc.
For me personally, I see that as a last resort, because Western medicine doesn't really understand how some of these herbs and supplements work or what they do. I don't want to stop the symptom of spotting at the cost of making it harder to understand the underlying cause, if there is one. Even acupuncture can have some unexpected effects - I've heard of some people who started spotting while having it, and others whose spotting stopped because of it! Maybe it's all a coincidence. Who knows!
Anyway, I feel like it's important not to worry or read too much into the spotting if everything else is ok, but do take this with a grain of salt. Hth.