got any ideas?

Hello Zombie, and welcome to the forum.  It sounds like you have a few issues going on here.  I'm not an expert but do have some experience with rescues and their various issues, so I'll offer a few suggestions. []

  Certain things will trigger this agression, sometimes Ill take off her jacket and she'll get mad.

I doubt the act of removing the jacket makes her upset (most dogs are happy to get the pesky things off []), but I'm wondering if you aren't sending her some "scary" body language without realizing it.  Do you lean over her while taking off her coat?  I ask because that's what I do with Cuma; its just the easiest position to be in.  However, you want to avoid leaning over a fearful dog , as it can be perceived as threatening.  If you aren't already doing so, I'd kneel down on the ground and even turn away from her as you gently remove her coat.

  shes really protective over her treats and food

I'm not sure how protective she is, but I first adopted Cuma, he didn't want anyone near his treats or food.  I hand-fed him his kibble for a week or so, so that he would understand that the food comes from me and I control it, and the problem was solved (we also took obedience class during those first few months, and that may have helped as well).  With serious cases of resource guarding, more work is involved.  I did buy this book, though I never had to use it: Mine! A Guide to Resource Guarding in Dogs by Jean Donaldson.
 
One other book that helped me a lot when I had a fearful foster dog was On Talking Terms with Dogs: Calming Signals by Turid Rugaas. 
 
One other thing often recommended here, and then I promise to end this lengthy post, is NILIF.  Google it, but basically it is a way to become the leader of your pack in a positive way.  By making her work for the things she wants (food, walkies, attention/playtime) she will become more comfortable with her position in the pack, and hopefully less fearful.  I didn't explain very well, but there's TONS of info here on that topic.

Re the food:
1.  If you free feed then I think you should stop and feed 2 regular meals each day, take the food away if she walks away from it at any point.  Letting a dog eat when they like undermines the NILIF programme and you lose out on a valuable opportunity to show the dog you are in control of her most vital resource.
 
2.  After you have handfed her for several days, put several empty food bowls in a row on the floor and have her dinner in a pot in your hand.  Drop some in the first bowl, let her eat, move to the next bowl, repeat, when you get to the end of the row work your way back, or go back to bowl 1 and start again.  After only a couple of reps she should scamper ahead of you to the next bowl and wait for you to approach and drop the food in - she is then being rewarded for being by her food bowl, aware of someone approaching and still relaxed and happy about it.  Repeat this as often as you can to show her someone approaching her bowl can be positive and she has no need to guard it from you.
 
3.  If she is crate trained you could try feeding her meals shut in the crate if you don't already.  This will make her feel secure as she eats and reduce her need to guard what she has because she's eating in the safety of her own space, her safe haven, and she is sure she won't be interrupted.  It also means no one walking by will get snapped at and if you even have kids visiting your house this will be an invaluable safety measure, so it's good if she gets accustomed to it.
 
Re possessiveness over other items, has she been taught "swapsies" (or "trade" or "the thank you game")  Basically she learns to give up things she has willingly in return for something better from you, and then often gets the original item back, starting with very low value things and working up.  This should reduce her guarding because she knows if you haven't asked for whatever she has, there's no competition over it and if you have its worthwhile giving it up briefly.
 
Hope that helps.

thank you, im going to check out the NILIF thing and see what i cant do =)