A quick googling of "pet medical charities" brought up a few pages, with these two being among the ones linked and each linking to charities for pet owners who are having a hard time paying for care. Couldn't hurt to contact some. Also doesn't hurt to donate when you have some free money, so there's more available for other people who find that their pet's health puts them in a bind.
When I think "therapist", I think of someone who tries to help you break out of of unhealthy patterns of thought. From things you've said, it sounds like your problems are more about your situation than your outlook. Even if you found a good therapist, I don't know how much they'd be the right tool for the job.
A psychiatrist might help by prescribing meds. But even if professional advice weren't against the forum rules, I have neither the training nor the understanding of how your mind works to say what might work. And psychiatrists, by dint of having been trained the way they are, can also fall into the trap of thinking that their first impression is obviously and unimpeachably Right. One might help if you can think of mood issues that you can't seem to shake and that are not just normal extensions of complicated life stresses. This is less for you specifically, and more because someone else reading this might realize that medication is what they need more than blanket "therapy". There are anti-anxiety drugs that some people consider essential, but I don't want to recommend those without a lot more information.
Just having someone to vent to and having ways to let off stress in general can often help, especially if you've spent so long walking on eggshells that you consider the high tension state to be a baseline. (Which I guess a good therapist could help you break out of, but the first thing they'd do would be to help you realize what not being perpetually on edge would feel like. You can do that without the stresses of putting yourself in a theraputic setting.) So the most important questions are, what can you do to help yourself destress, and how many people do you have who you can vent to so you don't feel like you have to carry it all on your own.