Hi , My Gums Are Darker In Colour When In

Hi , my gums are darker in colour when in childhood i go for checkups they always give me antibiotics by saying infection is to be treated it stops for while but starts again to bleed if i eat something hard or brush .
now a days i noticed specially in morning firstly my spit was dark in colour yellow then from two days i am noticing smallest clot of blood in the spit not each time but in the morning specially i am worried , help me out