I m 27, 64 kg. My period started 2 days ago. Yesterday afternoon I became very dizzy and almost fell down, and have been dizzy until I went to sleep , this morning I wasn t dizzy anymore but I feel as if I got drunk last night very lightheaded, nauseous, back pain . I ve been on the pill for 4 years, I had unprotected sex on the 29.04. Could I be pregnant despite the pill?