Are you abolutely sure you used to play football 3 times a week.. and cycle.... and run 50+ miles a week? All at the same time? Could it be that, in the mists of time, you're forgetting that you perhaps did one or two of these activities... but not all 3 every week.
Even if you did, you have to respect that you're into your forties now, whether or not your viral reaction is affecting you. I really think that if you're finding football 'very intensive' then it does sound like you're trying to run around like the 23 year old you used to be! This would be like a speed session for anyone.
In my opinion, knowing little about you, if you want to run high mileage, I think you need to cut football down to once a week. Maybe twice if you're ultra fit... but think about becoming the sweeper rather than the midfield dynamo.