We're sorry to hear about your trouble reaching the mikveh.
Inter-menstrual spotting is very common as a woman approaches menopause. This type of uterine bleeding can make a woman niddah or invalidate her clean days even when she does not have a full-fledged period. Even so, one important step to take is to investigate the spotting with your physician. For example, you may determine that there is a non-uterine cause for your spotting, which may not invalidate the clean days.
The other major step to take is to bring the spotted bedikah cloths to a rav for evaluation prior to starting over. Not all browns invalidate a bedikah. For example, a light brown with no hint of a reddish tint does not invalidate a bedikah. Other cases are best assessed by a rav.
It is sometimes possible to reduce the amount of bedikot a woman performs, which may be helpful in this case. For example, performing one bedikah per day (rather than two) would be fully permissible in this case. Further reductions are possible. If you think they would help, please get back to us with more details.
The above answer assumes that you are referring to spotting on internal bedikot. Internal bedikot with a cloth have a different, more stringent halachic status than external wiping. If the spots you find are on toilet paper, there is often greater room for leniency. (Please see our site's article "Toilet Paper" for details.) Even during the clean days, there is no obligation to examine toilet paper for spotting, and it may well be to your advantage not to do so.
Please don't hesitate to be back in touch with us with any further questions and please do be sure to ask questions before starting over again.