If you are physically unable to go to the mikvah, unfortunately you will remain in
niddah until you are able to immerse.
We do recommend completing all of the required
bedikot of the
seven clean days so that if you do have a good day which you are not bedridden, you may immerse that night. Once you have completed the seven clean days, you no longer need to wear white underwear or perform any
bedikot.
We recommend speaking to the
mikveh attendant about possibly having another woman accompany you into the mikveh itself, so that if G-d forbid you do get dizzy or are about to faint, someone will be with you to assist you. Furthermore, there are mikvaot which are designed to assist women with disabilities, including those who are always bedridden; if there is such a mikveh in your area they should be able to help you find a solution. You could also consult with an occupational therapist about possible strategies for immersion given your situation.
You might also want to discuss with your physician the use of hormones (assuming your medical condition permits this) to
lengthen your cycles so that you menstruate – and thus need to use the mikveh – less frequently.
We wish you a refuah shleimah!