Self Worth...Working, Losing Weight

It's amazing how my spirits jump up and down when I got called for a second interview for a part-time position.  I love the work, it's just that I go from flying high to OMG...I can't make it through even a part time position.  So, today I went and bought a black professional suit and black flats which is causing me anxiety because I can't afford it if I don't get the job.  Yet, I need it to go on the interview.  
From all the trying on, I got depressed because I gained so much weight I look and feel like a fat shit...then from trying on so many things and finishing in the lingerie department, that did me in.  My back started spasming so bad I couldn't even get a sentence out.  Now, I have swelling and irritation and need to lie flat to relieve the pain along with a pain killer.  Great future employee, huh?  I didn't mention my back issues the first time around.  However, when I was given a tour of the place, we had to walk down a flight of stairs.  So, going down is not a problem for me, but on our way back up, I couldn't do it!! I ended up crawling on all fours to relieve the pressure and then the lady turned around and saw me!!!UGH!  I brushed it off that I have back issues sometimes but if I just go down and stay down, or just stay on the main floor, I'm fine.  I just can't go up and down all day long.  One time down...and up/ day but definitely prefer if not at all.  My luck kicked in and she informed me it's on ground floor.  So, from the lot right into the place- no stairs.
As many times as I said I'm going to lose the weight I put on, I haven't done and I'm only bullshitting myself.  No one cares I'm fat and feel like shit...but me. So, today, without verbal notification to everyone around me, I promised myself to take better care of myself.  Depression is definitely there and I recognize it but only I can make that change.  
Feels good to write out whats racing in my mind.  I need to write more often so it calms my inner self.