Does No Periods With Dizziness And Lightheadedness, A Sign Of Pregnancy?

i am a 22 years old mother of 1 and i am feeling i may be pregnant, me and my partner are trying to conceive. i had the contraceptive implant removed in january 2011. my periods since then have lasted 7 days each, starting on dates: feb 4, mar 10, apr 13, may 22, jun 21 and my latest was jul 30. it is now oct 2nd and still no period. i have no other symptoms except for the last week been experiencing dizziness and light-headedness. i have taken several home pregnancy tests which have all been negative except one on the morning of 1st oct, a very very faint line appeared. could i be pregnant? or if not what else could cause this?