I Am Falling Apart

I'm having those days. But it seems like I am having a lot of those lately. I got to my 9am appt. I ran a few minutes late. It was on a HUGE hill and it appears to be in construction. I hate hills because my design bag is sooo heavy. Also, I hurt myself at the last construction site. I call the client, who doesn't even seem like he can make it. Before you know it, I closed my car door, with my keys still inside! I'm mortified! This is the 2nd time in 3 weeks!!! The last time this happened, the keys were in my truck and it took the guy 3 hrs to get it out! Luckily the construction workers helped me. I can't thank those guys enough. We were able to drive a small wire through the door and pull the keys through the crack. I'm having a really tough time at this job. It's one thing after another. Clients will milk me and my time, then decide to not buy. I'm running into stupid errors left and right. My car keys. Client issues. Clients not being at the appointments. Clients not letting me come by earlier. Then when payday comes, not making good money. I'm sick of it. Sometimes I wonder if this is all worth it. Can I keep going on at this job??? I feel so flustered and behind on projects and exhausted. Then I get angry. My lid is about to explode! I'm sooo tired. I don't hate the job. I'm just so drained. I don't know what to do. But most of all, I'm just frustrated with how I feel and what ends up happening all the frigging time...