I'm lost... I got my labs today and all my hormones are normal.

My testosterone levels are normal. Prolactin was suspected to be high. Also normal. FSH, LH... you name it. My fasting blood sugar is 78 and I don’t have insulin resistance. Yet I still have all the tell-tale signs of PCOS: slow weight loss, hirsutism, irregular periods. Sigh My doctor said this does happen and is often referred to as clinical PCOS. But how is that even possible? The only deficiency showing up is vitamin D. It’s around 21 when it should ideally be above 30. My doctor wants to put me on metformin to help regulate my cycle. And here’s what bothers me. I’m a weight lifter and a frequent runner and according to several medical studies I’ve come across, metformin can blunt exercise adaptations. I was initially excited and hopeful about starting it...but reading this has filled me with dread and anxiety as I only find comfort in a muscular/lean physique and I’m terrified of metformin negatively affecting my muscles. My doctor also mentioned that I wouldn’t be on it long term. Only for about three months to help get my cycle back on track. Is that actually a thing? Or will my periods just become irregular again the moment I stop taking it? I feel completely lost and broken right now. Please help me make sense of this. EDIT: For those concerned my testosterone is 48.29 ng/dL and my HOMA-IR score is 1.4. Both doctor and Grok claim I'm well within normal range.