Help!

I am on a pretty regular cycle of 26 days. I am currently 15dpo, 6 days late. I have NEVER been this late before. I've only ever been maybe 1.5 days late before. I've been waiting so long to get pregnant and I feel like I may be seeing things. My sister thinks I'm too fat to get pregnant and I just really need a win right now. I have been testing since 3 days late with multiple types of test and today I think I may see the absolute faintest of faint lines. What do you think?