Another Bad Day :-(

I don't know whats wrong with me (I know you're all saying- your pregnant!), but I feel like I'm having a lot of hard days lately and today was another one. What bothers me is that I know that it really isn't that bad, but my emotions don't get that. I have these struggles with Dylan and then all of a sudden I'm sobbing partly because I'm frustrated and then I cry harder because I can't believe that I am having such a hard time. I don't remember it being this bad at all when I was pregnant with Dylan, and I was working more and going to school full time. Sometimes I feel like crying for no reason at all. Please someone tell me this is normal! I'm also very tired, even if I get enough sleep at night I'm nodding off by early afternoon. My Mother-in-law wants to check my iron levels to make sure I'm not anemic because after I had Dylan I was extremely anemic. So I will do that soon and maybe that will account for some of my tiredness. Please just keep me in your prayers, I hate to have my mood-swings have an effect on my family.