Pre menopause and or MS

Hi can anyone tell me anything about this stage? I am 39 my periods are becoming less regular again, they were for years irregular and heavy then they settled down to a nice 31-32 day cycle for about 18 months now for the past few months they are all sorts of lengths from 28 days to 38 and now I'm on day 39. We'd love to have another baby, But it's been 8 yeas since our last with no successful pregnancys, I tested two days ago and it was negitive. But I've got a pain like a cramp in my left side, and I've been clumsy, past two years and not quite as sharp mentally for example using the wrong word such as go put your fork in the box insted of go put your pen in the box, or tidy the books insted of tidy the toys! It's strange. It may all be unrelated of course. My sister has been diagnosed with MS so sometimes I wonder if the any of its linked to that. I do have IBS, migraines and a benign tremor like her but I've had all these things since I was a young teenager. They are no worse.