Hows your crown? If you have no thinning at your crown you're probably good.
I had a good hairline until the last few months (when I jumped on finasteride)..so I never noticed how much I was thinning from the crown till i saw it in a picture.
I don't think it matters if your dad had a full head of hair. For all you know, balding could be in your mother's line. For a time in fact it was believed that male pattern baldness was inherited from the mother's side, even though we have then realized that's a bit of a myth.
I'd look towards your grandparents or siblings of your mother. But, in my opinion, you do in fact have a pattern going on. I'd like to hear other answers as I'm on the same boat as you.
After wearing a hat today my hair was all flattened out. Pulling my hair back on the left side showed this on my temple... Time to visit a doctor?
Looking at this picture I'd say you really have a problem. I remember when my hair was like that and nobody noticed I was losing my hair but me. Like you they thought I was crazy. Now a couple years later it's obvious to everyone, and I can't remember the last time I heard the words "you have great hair". I used to hear that all the time. Do something now before it gets worse.