TTC help please. Period issues

Hi Ladies. so I'm a bit concerned about the fact I normally have periods that last 5-7days now the last 3 periods they have only been 2-3 days long so I went to see a doctor to share my concern as I'm ttc and she said to me that she doesn't care how long they last at least I'm getting them. however I have read a few studys that suggest having short periods can reduce your fertility and increase chances of miscarriage (which I've had happen last year) .... so ladies what do you think. does anyone else have short periods like this? have you been able to concieve? please let me know thanks