Cutting off bus

Hello, I’m a new driver and been driving per 3 weeks now. Today I made a mistake and feel awful about it😞 . It shouldn’t have happened. One time I stoped near a shop and when I wanted to merge in the road I did it by going reverse and then when I was about to move forward I was near the traffic light and they went green after a few seconds being red. But behind me was a bus. I think I cut him off even though I let him go first then as I had ti move on the right lane because I was to the left and after the traffic light it was bus lane. I don know if I will get some penalty points or a penalty charge. I’m about to cry for being such a stupid!