Not sure if I'm worrying too much or not

I have health anxiety so it's hard to know what I should be worried about. I'm 23. Great Aunt had breast cancer in her sixties.

Before Christmas, I went to the Doctor about pain in one boob. He told me to wait and see if it was due to my period. It wasn't, so I went back again, said I had non-cyclical pain in one boob (began getting noticeable and bad in November). I was referred for an ultrasound. They only examined the most painful area which was the right side of my right breast and armpit. They sent me home with P2 glandular thickening. I still don't really know what that means, does it mean fibrocystic breasts?

In January, 2 weeks after, I found what I thought was a lump. I went to the GP and she couldn't find it. She said if it isn't constantly there, it's unlikely to be cancer. She said if I was sent back and they couldn't find it, they wouldn't scan, so it was best to wait. She did say to go back if anything changed.

It's hard to find. Some days I can find it, some days I can't. I don't think it's disappearing - it feels kind of hard and doesn't move. I'm scared lumpy tissue above it is hiding it. I really can't tell. I'm concerned about other areas of the breast too. It still hurts, I think it MIGHT be worse before and during my period but my period finished a week ago and the pain is still there regardless.

So today, I decided to go back to the GP again. For the fourth time. I asked to be referred back for peace of mind and to confirm I have fibrocystic breasts because everything online says "do not take your chances, even if you are young".

Today I was absent-mindedly reading my old diary and found "the doctor checked my boobs" in 2015. I have a vague recollection of going to the Doctors but I can't remember what was going on with my boobs. They've always been a bit lumpy but I don't think either one has ever hurt this much.

Yesterday, I read about Kris, founder of coppafeel, who was diagnosed with stage 4 breast cancer aged 23. It scared me no end. So women who get diagnosed my age usually have stage 3 and beyond because it takes so long to diagnose? Ahhhhh. What a brave woman. Now I'm thinking, I could have it. Today, I saw a picture on the homepage of reddit of a woman who has stage 4 cancer at 26. She commented "the doctor told me they are seeing an increase in women my age, apparently it's environmental".

I KNOW I should stop googling, but I'm trying to gage what I should be doing about this.

People are telling me not to be stupid and to stop worrying so I feel a bit alone. I can't talk to anyone because I'm boring them with it and they believe I don't have it. I don't know why, but typing this all out makes me feel good to get it all down somewhere. Thank you for taking the time to read. I'd love to speak to people going through the same thing? How pushy should I be with Doctors?