I would spend days in bed sad over the latest test result I got when I was ill. It seemed they were always coming up with additional diagnosis and I was always being sent for more tests. I would concentrate on "how sick I was" and "how I couldn't be the person I wanted to be" and would read books on my illnesses and go to online forums where people talked about "being so sick". I was focusing on my illnesses and I would WISH I would wake up one day and be healed but it was just that -- a desperate wish surrounded by all my negative thoughts. Before learning about the Law of Attraction or the mind/body connection I would never have dreamed that actually visualizing myself well and shifting attention to the few body parts that didn't hurt could influence my physical health.
It is certainly OK to realize what is not right in your life. Admitting what you don't want should allow you to shed a light on what you DO want. Knowing what you do want allows you to set goals, mini goals and plan for action to lead you to your final destination. The law of attraction says "Ask, Believe and Receive". In order to Ask you need to KNOW what you want. Some people have spent months or years concentrating on what they don't want, "I don't want to be fat", "I don't want to be poor" -- these are the wrong messages to send out. Turning them around and affirming them is simple. "I do want to be skinny", "I DO want to be rich". Not only are you speaking in positive terms but it is putting yourself in the right space for the next step.
Belief is an arguable point. Some people say that if you write down what you want and say it enough times it will come true. For me, I KNOW I NEED to believe in what I am trying to accomplish for what I want to come true. There were times in my healing process that I got off track and felt "this is hard". Sometimes I would have worse pain then I had experienced in a while. But KNOWING and BELIEVING with all my heart that I would make myself better allowed me to quickly get back into that space. I experienced set backs as you do in the road to achieving most goals. There were a few days when I had more stress than usual or a meeting for my invention didn't quite go the way I wanted and I would feel pain starting to creep its way back in. The difference was that I was focused on my end goal, believed it and would use that awareness of me feeling stressed to re-focus myself. I would tell myself "things won't always go perfectly the way you imagine them -- you have to learn to live with these little bumps and notice them and let them go so you can get on with your healing". I would also ask myself 'What can I learn from this experience?". Sometimes I would give myself a time limit to wallow in my sadness a bit. "Ok, Jen you can be upset tonight but you will do your gratitude list before bed and you will wake up feeling MUCH better".
Along with believing I think self-love and self-worth are integral to be in the right place to receive. Do you believe you are worthy of your final goal? Do you keep questioning whether or not this can work for you? You do not have to ALWAYS be sending yourself positive messages but are you MOSTLY sending positive or negative messages to yourself? Are you listening (REALLY listening) to your self-talk? Are you living consciously and believing you can do what you have set out to do? It does not matter what others say about your goal (if you have shared it) -- it matters what YOU believe. We often put a lot of self-limiting beliefs on ourselves as well as fear. There are methods to "let these things go". Meditation, EFT, NLP, The Sedona Method -- find a method that feels right to you and "let go" of the emotions that are holding you back from receiving. There are tons of videos available on youtube that highlight each of these methods for free.
No, you don't have to walk around in some fog "acting happy all the time" for the law of attraction to work for you. You DO have to be conscious of your self talk and what you are feeling and how you react when things "don't go your way". After all who are we to say we know exactly how things are meant to be? Life sometimes moves in ways we think are "bad for us" and it turns out to be the best thing possible. Try and find the lesson to be learned the next time something goes differently than expected, "let go of the negative emotions attached to the event" and refocus on your goals so you are in the right mind frame to receive.