Dont be too hard on yourself. Give yourself a break sometimes and some pads on the shoulder for wanting to deal with these things. You could just push it aside and fill your life with noise but instead you contemplate this and you try to practice daily mindfulness. That is great and that is what the Buddha taught us to do. So keep that in mind everyday that you are making an effort here. Its valueable. Not only to you but also for everyone who comes in contact with you.
When feelings of guilt, inferiority or other negative feelings arise just note them and observe them. If you observe them from they arise until the point where they cease you will see that they are impermanent. What is impermanent is also suffering since one cannot rely on it. Also you will see that you have absolutely no control over the feelings. Its not like you can say: bad feeling, go away. That will not work. All the aggregates are subject to the 3 signs of existence, namely anicca, dukkha, anatta, meaning impermanence, unsatisfactoriness and not-self. They are uncontrollable and ungovernable.
When you guard yourself with mindfulness and thereby being able to see e.g. feelings and mental formations arise and cease you will see that they do so on their own accord. Because they are conditioned phenomena build upon other causes which again is build by other causes etc., they will exist as long as the causes sustaining them is present.
Lets take the example with guilt. When guilt arises, note it, observe it and watch it until it goes away. See that you have no control over it. When there arises an object to the sense door, there will be contact and when there is contact there arises feeling. That feeling can be pleasant, unpleasant and neutral. When guilt arises, there can arise aversion towards that feeling. If that happens then switch to the new object which is the aversion and note it as "disliking". You can stop the process at that point or before that point if you are mindful about it. If you are not mindful or loose mindfulness for some reason the next step can be a bodily reaction to the guilt-based aversion. It might be heat in the body, increased respiration or other unpleasant bodily reactions. If that happens then swith to that new object e.g. heat in the body and not it as "heat, heat or warm, warm".
The point is that feelings, mental formations and the other aggregates are not subject to our control. By seeing that in insight meditation one begins to gradually let go of the aggregates and when that happens its results in more freedom and equanimity. One sees that one does not have to react to e.g. feelings and thoughts. They arise and they cease and thats it. Dont interfere with them. They will go away again. If you interfere with them you will blow them up in size. Its like putting fuel on a fire.
If you dont react to them and just note them there will be no fuel for the fire and it will cease to exist.
Ven. Yuttadhammo has made a video on youtube which i unfortunately dont remember the name of now. I will post the link if i find the name. In the video Ven. Yuttadhammo makes a simile of feelings and talk about how they can be viewed as a piece of burning wood taking from a camp fire. When one takes the piece of burning wood and puts it on the ground away from the fire, then it will burn for a while and then go out. No problem there. But if one takes the piece of burning wood and holds it in ones hand one will get burned.
So if you "take" the feeling of guilt and interfere with it you will get burned. But if you dont interact with it and just note it then you will not get "harmed".
Hope this might be of some help to you.