Could I Be Pregnant ?😬😌

Alright so my fiancé and I have been trying for a baby now &a every test I take it negative but the negative line keeps getting more faint when I take it. Could it be I’m pregnant but my levels aren’t high enough to detect it ? The first one was taken 2-3 weeks ago &a the bottom one I took 2 days ago.. should I take another one soon? If so how soon!?