Need a career change at 40. Just feeling depressed.?

Im 40 years old and here I sit. My girlfriend just dumped me a few months ago for a younger guy. He is more succesful too. A cop. They bought a house together with two dogs. Somethign i couldnt have given her since I work only as a concierge in a hotel and a sub teacher. I get so upset on why she left me. I loved her and now she sleeps in another guys bed while i sleep alone. I dont wnat to go the bars to meet peple. I tried dating sites and im attractive guy. But bars are out. At my age i want to be married. I want to have asolid career but it isnt happening! I am moving to chicago to find work. I have degree in political science. Im trying to find a career in Public relations or a lobbyist. I need direction on how to break into those two fields. I want to make something of myself before I turn 50! Im scared to death! I got to do it!.....I cant live liek this anymore or i will have two strikes against me--old age and being broke the rest of my life. I want my girl back too. Help me?