On Wednesday I took my pill a few hours late, Thursday I had sex and took my pill a few hours late again. Since that I have had pregnancy symptoms such as breast soreness (started friday), nosebleeds, heartburn and nausea (started today). Am I overthinking or could I be pregnant?

Probably overthinking, unless you're on a norethindrone or norgestrel mini pill with a 3 hour window a few hours late doesn't matter. However taking your pill consistently at the same time can help minimize side effects

also it’s extremely unlikely you would be having pregnancy symptoms this early