Performing tawaaf with long intervals in between the rounds

Q: Is it permissible to separate tawaf rounds due to pain? 

Example, I did a few rounds of tawaf one day and a few another day until the seven rounds of tawaf have been completed? 

In the above mentioned situation, if a person is unable to do complete seven rounds of tawaf walking in one go due to pain but can do it separately like the above mentioned situation, will it be permissible for him to do complete seven rounds of tawaf in a wheelchair?

Paying interest fees with interest money

Q: Is it permissible to pay interest fees with the interest received, from and to the same party. 

E.g. A bank rewards its client with an interest % for utilising a savings account. On the other hand, the same bank charges the client an interest fee for using its credit card facility. Can the client pay the latter with the interest received? As it will be returning the same interest to the bank.

Yellow discharge

Q: I recently went to a Muslim doctor and I mentioned to her regarding me getting yellow discharge now and then. So I asked does she consider it haiz and she told me no, maybe it's like an illness or something else but from what she knows brown is like dried blood but not yellow discharge. Can I take this advice from her?