Faint lines

Hello ladies! My boyfriend and I have been trying to conceive. My ovulating according to glow was last week. Yesterday afternoon I was extremely nausiated and throwing up until about 1am. On a whim I took a pregnancy test and it came back positive but very lightly so we ran to the store and bought another 3. They also came back positive but with a faint line. The 4th one looked like a negative. I've got heartburn with anything I eat and am nausea off and on! It's horrible :( anyone have any tips? Advice?