Hi there,
I would suggest that you get her checked at your vets and try to collect a urine sample to take with you. Make sure the sample is as fresh as possible (i.e. on the morning of the appointment). It is possible that these are behavioural changes and there may be no clinical problem but it is always necessary to rule out medical problems first. Has anything changed around the house recently? Even something that seems quite small may have upset her in some way. If nothing clinical is flagged up at the appointment it may be worth trying some of the following: When she cries to be let out to toilet in the night, go down to her, let her out and put her back to bed with minimal contact or fuss. She may have started to become fussy with food so let her have her dinner for half an hour only. What she doesn't eat gets taken away until her next meal time. Try not to give into her by giving her something else instead.
These are only very brief ways that you may be able to help her and I am happy to offer further advice but, as I said, you first need to rule out any medical problems.
Hope this is helpful!