Hi KT4
First of all there are few people on this forum that will offer medical advice. To do so would be wrong and potentially misleading.
Even on this site you can look up the symptoms of depression. Common ones are a lack of self worth or self esteme. Another is increased agitation, possible directed to other people. There are other symptoms that may ring a bell with you when you read them - https://patient.info/health/depression-leaflet.
Our brains are not hotwired to cope with many aspects of the modern world. Hence the fact that as many as 25% of adults are suffering from depression.
Most people will tell you to see your GP and I won't tell you anything different. What you describe sounds like stress/depression - but a diagnosis is for the doctor to decide.
You mention that you were nervous putting this post on. I may be wrong but this suggests you are quite young - quite often people become more relaxed about these things as they get older. The reason I mention this is that you may also be nervous going to the GP. If that is the case then can I suggest that you take a few notes of how you feel, your circumstances, what reactions you have in certain situations. It's very difficult to get across all the necessary information in a short appointment, particularly is you are apprehensive.
My brother is a GP and confirms that a very large proportion of patients are there because of stress or depression. So whatever you say to your doctor he/she will have heard similar issues on numerous occasions.
If your doctor decides you are depressed he/she will probably try a first line antidepressant, Prozac for example. It's really important to be prepared for feeling possibly a little worse for the first 2 or 3 weeks. Also be aware of the side effects which mostly lessen after a while. A lot of people respond well to Prozac so you could notice your mood improving after a couple of weeks.
Some of your issues seem to be exacerbated by relationships. Along with medication I believe your problems will not go away unless you attend counselling, possible with your partner. Most practices offer Cognative Behavioural Therapy - fancy name for simple techniques to change negative thoughts into more positive ones - for example to control thoughts of rage.
To answer your question - without a doubt visit your GP. Make sure he/she understands everything and do not be afraid to ask for additional effective help such as counselling and CBT, If you delay then the way you feel and coping with relationships are just likely to get worse and harder to rectify. There's no magic drug, counsellor or CBT techniques - they are there to allow you help yourself and, if necessary, identify changes that are required in your life.