No one is perfect. Even great drivers have momentary lapses of concentration that could result in a minor ding or accident and the fact that some people have never had an accident is partly about luck as well as judgement. How many people have had near misses, for example...
Parking-type bumps are incredibly common among learner drivers. Although it would be better to not have them, the upside is that you learn from them and develop a better sense of spatial awareness.
The roundabout example is a classic case of inexperience, although it's one of the most common types of collisions. The rule with this one is never assume the car in front of you has gone until it's actually gone.
I've had one accident - on my very first day as a junior lecturer when I noticed the woman I had driven into (in the car park, minor prang) in the front row of the auditorium.
That did my nerves a lot of good.
It did make me a better driver though, as did gaining my motorbike licence - which certainly taught me how to drive defensively.
Accidents should be taken seriously. Unless you are blameless, they should be taken as a sign that you need to brush up on your skills, reaction times and road awareness, but they don't necessarily signify that you are careless. The loss of confidence that comes with them is part of the learning curve, and provided you do something about that message you can become a better driver as a result.
However, Nutritious I really feel you need to change your lifestyle or take some extra lessons. That's really not typical and if it continues it is only a matter of time before you have a serious accident. Tiredness can affect performance more than alcohol, so it is worth looking to see what you can do about your sleep or if you can lift share on days where you know you are going to be so tired. Also, 6 burst tyres? Unless you are driving on unpaved roads regularly, it sounds as though you're not checking your tyres regularly enough, which could not only land you in trouble with the police but could cause an accident even when you are driving very carefully.
OP, take this seriously but try not to be too hard on yourself. Accidents happen. If no one is hurt and you learn from them, they can turn out to be a blessing in disguise.