too early to tell?

My husband and I just decided to stay ttc for baby #2. With our first, I was expecting the usual 3-6months to conceive, but was surprised to find out we were pregnant within a month of stopping bc. I've never closely tracked my fertility, but according to this app, 1/10-1/16 was my fertile window. I didn't have many of the typical symptoms with my first, but this week, I have been fatigued, irritable occasionally queasy, and get short of breath easily, when I've always been pretty fit. I told my husband it's too early to test, and AF isn't due for another week. I randomly decided to take a test last night while he was gone, but I lost the instructions and didn't know how long to wait. After a couple min, there was no line, but I set it aside to put my 18mo old to bed. I didnt look at the test again until this morning, and noticed a faint +. I plan on waiting for another week to test again, but could it already have picked up if I am pregnant, and has anyone else noticed symptoms so soon?