Weight Gain, Bloating And Swelling. Irregular Periods. What Is Causing These?

I am a marathon runner, averaging for the past 7 years 40 miles per week. i complement that with weight training several times a week. My diet is vegan, plus carbs (like pretzels) for long runs My problem is now that i am approaching 47 and get my period perhaps 8 times a year, my weight gain of 10 lbs bloating swelling . i am frustrated since my eating is correct, i cannot exercise any more than i currently am. what is my solution?!