Irregular periods and Spironolactone

Hi, I am a first time user of this website and have a question about spironolactone. Up until about three months ago I was on Diane-35 for about a year and a half to control the acne but because of the increased risk of stroke (I get migraines) had to discontinue using it. I have been taking the spiro for about three months now to deal with acne. I was taking 25 mg daily at first, and upped it to a dose of 50 mg within the first month. I didn't have any side effects at that time. I have upped the dose to 100 mg over the last two months. I have recently (within the last month) experienced irregularities with my menstrual cycle and have had spotting (which I have never had before in my life). The question is, whether the irregularity is due to stopping birth control or increasing the dose of the spironolactone. I have read that increased doses (100 mg or higher) tend to increase the likelihood of having irregular menstruation. I have spoken to my doctor and she said it could be caused by either going off birth control or by the increased dose of the spiro. I have read that the irregular periods usually subside after three months. I guess my question is that I have only upped the dose to 100 mg in the last two months (even though I have been on spiro for three months total), so do you guys think that it could still be within the time frame that it could still fix itself (in that my periods will return to normal)? I have been told by my doctor to try lowering the dose slightly (to 75 mg) to see if this makes a difference. I have had acne for a long time and the spiro seems to mostly correct a lot of it. The period thing isn't a huge deal but it's really an inconvenience. Please let me know what you think, I would appreciate any advice that you have. Thanks in advance.