Feeling in control doesn't apply to TTC or pregnancy - both are nearly entirely out of your control. Of course you can set out to use OPKs, do everything by the book, stay super healthy or use black magic like raspberry tea. But this won't help you much. You'd be best of having a lot of sex and relaxing. And trust me, I know how annoying this advice is because I hated it myself when I was TTC. When I finally got pregnant with DS, I gave up hope of ever having a successful pregnancy, we spent all our savings, bought a project house and thought, oh fuck it. We knew there was nothing wrong with us because tests didn't show anything. I decided to leave it for a few months completely, next month I was pregnant, and whilst I had a very difficult pregnancy for various reasons in the 3rd trimester, everything ended up ok. I had no faith left in me.
As I'm very much like you, OP, I like what you call being proactive and in control, I will say this in a kindest possible way, it will be best for you to get out of this frame of mind asap. You can't control the process, its success or failure. Having this attitude will ramp up the pressure you're already putting yourself under and this will make things even more difficult. This is how anxiety begins when it comes to TTC and pregnancy and I very much agree with pps that you could benefit from MH therapy now.
Those who say someone else getting pregnant doesn't affect OP's fertility. Of course it doesn't. But the OP is now in a position of slowly becoming sidelined because there are more and more babies born to her friends, colleagues and within her social circle. Without a shadow of a doubt, lives of these women will change massively and even with the best of intentions from both sides, it'll be a hard period for OP who wants to be in their shoes too, but it hasn't happened yet. This shouldn't be underestimated. This really isn't about a very one-dimensional consideration that her chances of getting pg aren't worse regardless.
I will also say, OP, baby aspirin, cyclogest, extra strong folic acid or whatever it is that you're thinking of stocking up on or taking aren't a good idea if you don't have a reason to take them. Put it bluntly: a 32-33 yo who is fit and healthy and TTC for 7 months so far has zero need to take anything extra apart from standard folic acid/standard pre-conception vitamins. It's unhealthy and unhelpful to tell yourself that you 'need' the extras as it exacerbates your anxiety that something might be wrong with you, that's your fear, not the reality. Please try to ground yourself and give it a bit more time and patience, then if after a year or two things aren't happening you can start exploring other avenues.