Well there are several people who have been taking 50,000iu/daily for a long time and who still seem to be posting without any detriment to their health or apparent impact on their cognitive function. It is theorectically possible that 40,000iu every day for many months with sun exposure could cause such high levels of 25(OH)D that hyercalcemia could occur. But the experience of many people here is that 50,000iu/daily is not dangerous whatever I may say is theoretically possible. I suggest 50,000iu once a week as this is MORE than you body actually requires each day (4000iu meets daily needs 5000iu allows a little spare) and 50,000iu/week averages 7140iu/d which is well under the calculated safe upper limit which is 10,000iu/d (officially it's still 2000iu/d but everyone knows that is ludicrous and is there simply to show how slow health professionals are to come to terms with reality)
Hope it works out. But do give it time.
There are over 2000 different gene actions in your body governed by vitamin d. That means vitamin d switches on or off these 2000+ different switches. Each switch that isn't switched on at the right time or doesn't switch off when it should causes a different condition.

In your brain alone there are 180 different proteins upregulated by vitamin d, so that accounts for a huge set of brain dysfunction conditions that are all avoidable if we had sufficient vitamin d available all the time to ensure all those protein control switches worked as they should.