no definitely not. being an international student is exciting(!); you're on a grand adventure, experiencing a completely different country/culture. pretty sure about 20 percent of my undergrad was international, so it's not like if you are an international student you are anywhere near alone or special.
no, UK students do not reject international students but i won't lie to you: in my experience international students do tend to stick together, i think just cause they have 'that' in common. also a lot of kids in my class came from the same country, so they tended to befriend each other. i'm pretty sure i was friends with one fellow Canadian specifically because we could reminisce.
i don't know about the accents but i think it's just something we all deal with and pretend politely to understand when sometimes we don't. you'll find not all british accents easy to understand all the time either. doesn't stop you from being friends.