Hello. Thankfully your initial tests have come back normal and they can't see anything wrong them which is a good sign. The specialist appointment is a bit scary to take in at first but they may be able to do more in-depth checks to put your mind at rest that this is just a natural shift in your menstral cycle and it's normal. I spoke with a sexual health nurse in January and she said it was completely normal to have a shift after 35 -40 and I would need to get used to it. Sometimes she said she would have 3 mini periods between her normal pattern and it was to do with your body getting ready for the looming menapause. Even in your 30s. She did ask me to make an appointment with my doctor for the heavy part to my period but when I mentioned this to the doctor she wanted to do precautionary checks on the bleed anyway just to rule out anything sinister I think. 
 

Just having the same thing as you since Christmas. Bit of background. Has cin2 cells removed at 20. Since then my periods although heavy and clotting have been like clockwork and 7 days long no spotting. Since Christmas had bloody pink discharge day 9,12 of my cycle after I finish my period day 8 which last one wipe them disappears. No other obvious signs of bleeding the rest of the cycle and no bleeding or pain after sex. Spoke to doctor yesterday snd she's precautionary sending me to for an internal cervix check and having swabs for infection, std i imagine and I think from what she said a Pap smear as regular smears are screening not diagnosis of problems. My last smear was clear no hpv. 
 

she said it could be a number of reasons but they always investigate a change in period pattern and random

bleeding. Could be age, weight (I've put on 2 stone in lockdown) she mentioned something about my thiorid doe to gain but I think my weight gain was covid lockdown and drinking too much  infection, curvixal erosion or something else. I also read an article yesterday about anovulation which is when your body doesn't release an egg and your estrogen levels drop and you spot as your hormones are out of sync. Very common again leading up to your 40s. I knew about ovulation but not spotting when you don't produce an egg so it could be hormone changes although the doctor said they don't  really test for that. They check there isn't anything sinister then diagnose that at a later date. This would cause you to have heavier bleeds which are called withdrawal bleeds. And I've certainly had heavier bleeding which was the reason for the initial call to them yesterday. 
 

She did say she would be sending me for an ultrasound to check womb to to reassure me that everything was okay. 
 

I'm 43, I have 3 children no miscarriages. My other symptoms which she said could be a sign of perimenipause are

anxiety, feeling of dread all the time even after my anxiety medication, sore boobs.