Talk to Gynecologist on Irregular Bleeding

I always have my periods on time. I have age related fertility issues. I wànted to convince so doctor suggested me Estrolet 2.5mg but I experienced spotting before my periods date ànd periods got prolonged to 11 days. I was very worried about it. Then I did twelve day scan and Dr said Egg size was very good and prescribed me ferti-C. I did all this then I got spotting within that Same month now it's almost 8th day and I am experiencing irregular bleeding sometime it's heavy other time it's very light. I am very worried what should I do now. Please reply