Feeling overwhelmed and struggling to think straight

I'm a 38 year old female. Up until about 5 years ago I was fit and healthy- running around after my young kids, starting my own business, studying for a masters degree, taking regular 8 mile walks with my dog, enjoying daily yoga, running, enjoying life as a wife and mother. Then I started getting sick in one way or another and was suddenly getting diagnoses flung at me- IBS, Roseacea, PCOS, severe Cervical Spondylosis, Disc Osteophyte Bar Complex, Foraminal Stenosis, Chronic non-allergic Rhinitis, Migraines. Last winter I had back to back lung infections and was given steroid and antibiotics, I've been given an inhaler, steroid nasal sprays, various gels and creams for the rashes on my face, Nortripyline for the nerve pain. I take all my meds, I go to physio, I talk to doctors and neurosurgeons about this and that, I try to follow all the advice, but the one question that nobody seems to be able to answer for me is WHY? Why is all this happening? Is it all somehow linked? I went from being active and living my life to being unable to stand upright whenever I get menstrual cramps, having half of my left hand numb, dropping things, losing my balance, passing out randomly, constant pain, not being able to walk my dog or pick up my children, abdominal cramps, dizziness. I'm anxious to leave the house in case I start feeling ill or faint, I'm considering putting a pause on my business because I can't keep up and I have to ask for an extension on my final paperwork because I've fallen behind. Everytime I've asked a GP why this new thing is happening I've been told "maybe stress", "these things happen", "hormones change", "some people are just unlucky", "make lifestyle changes". But I feel like there must be some reason, surely, why all this has suddenly started happening in the last 5 years? It can't just be bad luck can it? I feel as though I'm going crazy and suddenly my body terrifies me and I don't know who to speak to or what to say. I'm worried about the loss of income for my family, and also the loss of who I was because I feel like a completely different person now- I barely leave the house unless it's for a medical appointment. I don't even know if anyone here can advise me or what I'm even asking for, I'm just feeling confused and overwhelmed and would like to feel sane again.