My senior cat has a chronic illness and needs to take a liquid medicine for the rest of her life to keep her healthy. While she's still largely happy and energetic now, if she doesn't get this medicine, she's likely to decline very quickly.
Unfortunately, but not surprisingly, she hates getting this medicine. When she realizes I'm giving it to her, she'll try to run away, and sometimes she struggles hard when I administer it, flailing around in a way that I know has to be very uncomfortable for her. Sometimes it goes great, though, and it's over so quickly that she seems more bewildered than anything else.
What really bothers me is that my relationship with her has soured quite a bit since I started giving her this medicine. While she still trusts and loves me more than not, she's definitely anxious when I move my hand towards her head. She's no longer certain whether to expect pets or medicine. And after I give her medicine, she'll sometimes get pretty ticked off at me. These bad moods can last for the better part of the day as she hides under a bed and slinks away from me if I try to climb underneath to give her attention.
I'm not sure how to proceed from here. My cat really needs this medicine, so not giving her anything isn't an option. I can take her to the vet for regular (and much more infrequent) shots, but that medicine isn't as effective, and things haven't gotten bad enough that I think the decrease in effectiveness is worth it.
What can I try to be able to continue giving my cat her medicine while regaining her full trust and ensuring our relationship remains a happy one?