What is wrong with me? He thinks I'm cheating, and I feel like I'm having a break down.?

I'm stuck in a bad position. All the signs have pointed to me being unfaithful to my fiance and in the last week I don't even know that I'd trust him if things were reversed. To make it worse, I have cheated in the past, but we had moved past it and things were going well. We have been together almost 10 years. But last week I got in contact with an old friend (male) and we ended up having a kind of ridiculously long text conversation over a couple of days. A few times the conversation went in a direction that I wasn't wanting it to go, and I tried to keep it on track and friendly. This is not the person that I cheated with, nor someone that I slept with, but I feel guilty about some of the things he said but I was feeling really down and lonley and needed someone to talk to. Then my fiance called me very angry about the number of text messages being sent on our account, and I apologized and made up a dumb excuse and stopped sending texts. But the phone company ( we have Sprint) logged another 90 texts after he called me. I told him I had sent no more but I'm sure he didn't believe me. Then our son emptied my purse on the floor and he said there were condoms in it. I told him that our son had been playing with them a while ago and when I took them away I just shoved them in there because it was handy. Which was close to the truth except that I had shoved them into my school bag ( this was MONTHS ago) and the other day they had nearly fallen out n cl and I was embared so I stuck them in my purse in the little zipper pocket and hadn't gotten a chance to take them out. But all of this is starting to stack up into a pretty convincing case against me. Then last night he calls me at work ( I work the nights that I don't have cl, which is another strike against me because I am rarely home in the evenings and it isn't unusual for me to be at work untill 3am) He is furious because he says that he got Sprint to send him the text and picture log from my phone and that while he hadn't gotten the texts yet that someone had sent me a picture of their in the photo log. I told him I never saw the photo, that I hadn't gotten it because I hadn't. I would remember someone's popping up on my phone. But I don't know why he would lie about it and honestly I can see the person the picture was from sending the picture, but the fact remains that I never saw it. At any rate, now he's just stewing at me because he's convinced that when he gets the text logs that it will be some huge exposition of a torrid affair. I'm just sick at this point. I have issues with depression and anxiety as it is and this is driving me up the wall because I know that even with the logs showing me steering away from my conversation being anything but friendly he will still see it the wrong way. I don't even know what to do anymore. I know I deserve the lack of trust, I messed up before and I accept responsibility for that. But what kills me is me feeling like I need to lie to him about things that I shouldn't have to lie about. Feeling guilty when I didn't do anything wrong. I have actually thought about how it would be easier to just avoid the whole confontation by hurting myself. I know that's not ok. I know that there is nothing that would justify killing myself. I know that. But I still think about it sometimes, which makes me feel even guiltier. I actually started punishing myself last week, making myself go the day without eating, seeing how long I could go without food. And the sick thing was it felt good, it felt good to feel hungry, to feel my stomach hurt. And then I started thinking about cutting myself. I almost stopped one night on my way home and bought razor blades because I couldn't bring myself to use the kitchen knives. I just want to make it all go away. Things were already strained because of the financial burden I put on us by going back to school. I feel like I've ruined his life as well as my own. And now I'm putting him through even more torment because of all the suspicion. I guess I'm just rambeling at this point, can anyone help me with something other than see a doctor/therapist? ( I would if I could, but no health insurance and no money kind of rules that out)