So confused (comments are appreciated!)

For the past few weeks I've been having early pregnancy symptoms ; (sleepy, frequent urination, acne, flutter feeling in my stomach like I'm going to get my period but dont, my nipples are so sore and this morning my boobs felt so firm and really heavy I even made my husband feel them because they've been hurting for 2 weeks but today they're even worse!! We ttc in the second week of August, and I had "2" periods so to say last month. I have taken tests all 3 times were negative with the little 88¢ ones from Walmart, Idk what's going on! Am I testing too early? my app says that I am 18 days into my cycle, haven't missed a period but I started feeling this way last month, so I'm confused!