PLEASE HELP ME

I'm 15, and have had symptoms from  3 days past ovulation onwards. I'm now at 11 days past ovulation and have experienced a variety of questionable symptoms, such as frequent need to urinate even if I have recently gone, headaches, extremely sore and swollen breasts, tingly nipples, slight nausea, bloating, constant fatigue (recently always seem to be tired despite getting good-average amount of sleep), lowered appetite and sharp period-like abdominal pains. I'm unsure if these are enough symptoms to be stressing about, but I'm wanting to get a test to make sure. I'm really worried about buying the test as I'm usually mature and I had clearly made a stupid decision and I don't want people making assumptions or looking down upon me. I also work and have Christmas quickly approaching as we all know, along with my mother being extremely protective of where I go and why. If I test on day 11 will it show a true result? How do I buy it with so many nerves? What to buy? Do I need to buy one? My friend said she could come but she also has work and lives 10kms away from me with no transport until after Christmas. I haven't spoken to my boyfriend yet. Please help me!!