describe,
are you going into a trance, falling asleep, so you lose track of your counting ?
are you wide awake, but losing track ?
if you are falling asleep, then i suggest that you learn to meditate on a mantra instead, when you lose track of the #s, pick a mantra, such as Om, Om, Om,
Om,
Om,
Om,
because Om is easy to remember, and it MEANS something, (a lot of things!!!!!) so it is like taking your cellphone and dialing the universal mind.
75 means something (dunno what ) but not as significant...
there's a story of a fellow in some country who is doing work for his father, counting out scoops of food, whenever he gets to three he goes into a huge trance, because the number three in their language sounds a lot like "Om" so he keeps scooping and scooping and scooping and scooping "three, three, three" (Om, Om, Om)

to stay awake in the trance state and focus, very slight sips of coffee or green tea can help, so that you are more alert, but still capable of enterting relaxation
but truthfully it is the mantra, drinking LOTS OF WATER and being hydrated, and practice, that will let you stay conscious in a trance... and even then its not like you can "think" or do much deliberately, its just that you don't "nod off"