Orgasms..

So I masturbate regularly and 100% always orgasm, through clit stimulation since I am not able to reach a orgasm of any kind during penetration wether it be through sex or masturbation. When I masturbate the most exciting and enjoyable moment for me is the build up to the orgasm. Recently the last 3 times I've masturbated mixing between fingers and vibrator I have reached a orgasm but I don't experience any build up and somewhat can't even fell it happening? Idk if its because i just started my period and maybe my body is just not into it or if its another reason. I have never had this problem before so I feel a bit discouraged.. does anyone have any tips or any clue why this is happening?