Why did this happen?

Does anybody else just not know why one day they were perfectly healthy and enjoying life and then all of a sudden was hit with a slew of dysautonomia symptoms? I still have no answers. Life used to be great and I loved living it. Now I dread making plans because half the time I feel like I've been poisoned. Definitely have POTs symptoms but the high heart rate isn't the biggest issue for me. Nausea, bit of temperature dysregulation, occassional tremors, fatigue, neuropathy symptoms, dizziness, weakness, twitches, headaches, weird GI symptoms, pre syncope, adrenaline surges, some chest pain...probably more! But also a general feeling of brain fog...or just as I said before, a feeling of being poisoned and not functioning properly. Anyone else the same and not know why this happened? I'm 35 with 2 young children and feel like I'm 80!