We’re sorry to hear of your challenging, shorter cycle. In this case, based on the information given, the five days prior to counting the clean days cannot be shortened. If there are additional factors you have not shared with us, please get back to us.
However, it may be possible to regulate your cycle medically in a way that would allow you more time with your husband. Please consult your physician as to the available options. You can direct him or her to the section of our website designed for medical professionals, Jewish Women’s Health.
One other step you could take is to review the laws of ketamim, stains, just in case you are not in fact becoming niddah as often as you might think. A flow of blood does make you niddah. However, not all stains, and not even all colors of blood, make you niddah. See our article, on stains for more details.