I too have had hair regrowth. Being very bald (Norwood 7 or so), I thought I was condemned to a shiny smooth head. This was from around age 45 (51 now). My hair regrowth on Finasteride filled in to an extent about an inch around the edges. After about a year on Fin, the fine, colourless hair started up. it is now starting to show colour too. I have been on HRT for about 2 months and I do not expect to see much improvement for a while yet if at all that is from HRT although the DHT hit from Fin may help.
Where hair loss is relatively recent and appears as thinning, then there is hope. In my case, having a full head of hair would be a miracle. Some coverage is all I can expect. Fortunately, while I am on Fin for MPB, that isn't why I am on HRT and any upside hair-wise is most welcome.
To the OP, I suggest you take action on the hair loss. If you are freaking out, good. Get moving on it. As others have already posted, there are treatments available.