While usually temporary, culture shock is common among international students arriving in the UK. You will notice differences between the way things are done and what you are used to at home. These include the way people dress, speak and behave, teaching and learning styles, food - potentially all aspects of life.
This can be frustrating and disorienting at first, as even something simple like buying a bus ticket needs figuring out - can I buy it on the bus, or from a shop or kiosk? Do I have to validate it? Does it cover a single trip, or a set period of time?
You will soon learn the new "rules" to get by, but it may be reassuring to know that it's perfectly normal to find it hard at first. Your fellow international students will share the experience - but so will many UK students who are away from home for the first time.