Early strange period

Hey!! So im a little bit worried my fiance and i had intimacy during my last day of my fertile window my period often comes after 30 to 35 days... and now i had my period after 28 days and its not as usual as my other periods... its not a really tiny amout of blood but its not as much as my normal periods. The first day i noticed a pinkish spotting the second day i had alot of red blood the third day the same(red and a normal amout) and the fourth day its just a light brown and just a few dots... tjere were no cramps no pain at all so should i be worried of being pregnant? Oo and i have 0 pregnancy symptons... please comment! Thankyou!!!!