Along with what Leif said (and I can personally validate its truth, since I've been homeless before, as well) there are things such as violence (from both other homeless, and from those who aren't, who will take out their sadism on you), drug addicts, alcoholics, molesters and rapists (men are not immune), and thieves. There's being harassed by the cops, who can come in your camp, if you have one, and destroy everything you own, and beat you up - they do it, I've seen it - or just jerk you around, personally. There is no such thing as finding a safe spot. Unless you keep yourself really clean, and looking half-way normal (very difficult as most places don't have public restrooms, and if they find you in one, you'll get kicked out) most businesses aren't going to allow you near them.
Forget finding a job, if you're homeless. Not only do you not have a physical address, but you're going to be sleep deprived, as well as not having access to shower facilities on a regular basis (unless you're in a shelter, and still many of these things will continue to apply even in a shelter).
Oh, yes, shelters. Most are Christian based. If you're not religious, you're going to have a hard time. And rules? Forget staying out late, forget having a drink (in many of them), everything is on their time, their rules, and many of the people who work in shelters are ex-homeless: therefore all of the above worries about theft and other things will still apply. Shelters are just that, a roof, and many homeless refuse to go to them due to lack of safety issues, and an over-abundance of "you're a guilty sinner" condemnation. The other alternatives are drug-rehab based, and they tend to frown upon people who don't need their services. Seriously, been there, done that - if you don't have a drug or alcohol issue, you're kind of screwed. (For that matter, if you're a woman who isn't raped, beaten, pregnant or has a passel of children, you're screwed, too.)
Many people "live out", if you're in a smaller town area. All the above still applies, but sometimes its a bit safer. My friend lived in a camp, by himself, on the river, and would fish, and come into the shelter at nights to get dinners there, or to use the shower (oft times you can't use the shower facility unless you spend the night). He survived 16 years living out in the woods like that, coming into town only once a week, sometimes. He now has emphysema from being out in the weather for all those years, and when he finally came to live in town he was hospitalized for a while for malnutrition. It took him years to finally be able to live around people again.
Being homeless causes Post Traumatic Stress Disorder.
If you have viable options beyond being homeless, I'd
really suggest you look into them. Checking yourself into a hospital would be better than checking yourself into a jail, and it wouldn't affect your records permanently. Being homeless, even for a day or two, would only make things worse. I promise. And I wouldn't like to see things get worse for you, or anyone. :hug: Good luck.