Why do I get so annoyed so easily?

i use to be like this towards my family but never my friends. When i was around 15 i started getting very aggressive and i use to always get irritated very very quickly at the most smallest things. I did go to my doctor about it, and he asked what makes me happy. I told him photography made my happy and he said to take about 30 minutes to myself and take some photos and do what makes me happy and continue it everyday. This way i get time on my own, some breathing space and it clears my mind - and hey, at least i've done something i like everyday. So do the same? He also told me that i feel very overwhelmed, it's normal for any teenager (that's if you are one?). Go see your doctor if you want. Also, instead of slashing out, just take deep breaths and move past what irritates you :)