Are my expectations too high for my teachers?

I have a few teachers who always say things like 'I'm losing my family time from marking your work.' but isn't that part of their job??? They also only mark like once a month. Today, one of them said 'You guys come up to us while we are eating and that is so rude.' but like we (students) were told to go to them during lunch times to ask about things we don't understand ? and we can't ask during lesson because we always can't find a chance to talk to her and during the end of the lesson we have to rush 3 flights of stairs down to our other lesson asap? Why are they always complaining about things that are required in their job when they chose this path themselves? I miss having teachers who actually want to help me improve. Am I just being overly sensitive? And are my expectations just too high? Maybe i'm being completely ignorant and selfish... I'm just so worried for my GCSE and have many things to discuss with my teachers but I feel like I can't because they all seem to be annoyed.

I think it is rude to go up to people when they are actually eating their lunch and ask for help. The appropriate thing to do would be to ask them during a lesson if you could make an appointment to see them one day after school (or before school in the morning) to discuss your problems with work. Teachers are entitled to a lunch break, it's a legal requirement.

Thanks for the reply, I appreciate it but after school or before school would be inconvenient for both me and the teachers due to meetings and such. Also as mentioned above we was taught to go to them during our own time (break and lunch). However, I do understand your point so I tend to email them and try my best to ask them when they are free during the lesson.