Pregnancy Questions..

Has anyone ever heard of "cryptic" pregnancy? A friend rescently told me I may be... I had a miscarrage March 17, didnt realize it was close to my ovulation time and had intercorse April 2, Ive had all the symtoms, some milder than others but all there. I havent had a peruod at all. thats not like me, im in my 20's. I have been pregnant a few times, I have one child. and honestly, I feel pregnant now... i took a home pregnancy test, it said no... then another a few weeks later. still no. is there a way my hcg level could just be low maybe? or is this just in my head..? any advice, appriciated thank you, have a blessed day!