Motivation is the Key

"People often say that motivation doesn't last. Well, neither does bathing - that's why we recommend it daily." - Zig Ziglar.
As per the quote we really need the motivation daily to get focused or get achieved the works or goals we need to do. And like bathing it does something like refresh our souls and revitalize our inner capabilities.
And which problem you're facing now is a very common problem to all of us. Relating
to your problem, to me there is no negative motivation exists. All we have is the positive. I explain. Suppose, you're just fired up from you company and what will be your thinking, yes it's dissapointing, it's frustating. But believe me, this is your big opportunity to prove yourself, to make yourself world-class. Because, every rejection, pain, loss, sorrow are just shaping us through out our lives. So, after being fired up from the organization,if you ask yourself - "What's the gift here?".... I know you'll certainly get the answer and that answer may act as your motivation as that very moment. So I'm asking you, will you now refer it as negative incident or negative motivation? Always remember - God will not give you anything you can't handle." May be it's loss, pain, win a race among others.
You may ask me that may be I've not comprehended your question properly. But, I did. Let me clear you that the main problem of yours is not lack of motivation( because we can be motivated by our simplest daily incidents, even if it is not our cup of tea also). You need something which rekindle your spirit again to achieve your dreams. So, I suggest you some simple steps by which you can get the needed boost.

1. When you feel frustrated, or demotivated, just close your eyes and take 3-4 deep breaths and concentrate in between your two eyebrows for 5 minutes. You can see the result. It's a practical one.

2. It's a principle of dying daily. Ask yourself a single most powerful question and see the result - " What would I do, if this was the last night of my life?" This is a question which does wonders for the Apple CEO Steve Jobs. It;s a powerful question which will keep yourself focused and help yourself to prioritize your most important works.
3. Write 2 or 3 quotations which attract you, inspire you , motivate you on a blank piece of paper and place that paper in your purse and where ever you go, just check out those every half an hour. And see the result.

4. After waking up from bed, close your eyes and affirm " Thank you God for giving me this day, this 24 hours, this very minute and all the blessings (may be it's your family, your understandable partner, your communication skills, your leadership ability among others) that you gave me." This is for a perfect start of your day. It will fill up postivity into your days and move you to the level of extraordinary.

5. Do one thing atleast everyday, which fills your heart with enormous joy and which love to do the most. May be it's listening to soothing music, singing a good note, playing badminton, riding bicycles etc. Because that injects more unforgettable moments into your days and your days will not be the same.
I've explained the 5 rules which I think can have the power to motivete you daily and get to you to the next level. I'm really eager to know that whether you're benefited from my suggestion or not. If I can help you to increase your motivation even upto 1%, then I think I'll be honoured. So pls do inform me about the results. I'll just love to hear that.