I've been in a lot of LDRs in my time, and eventually I realized that several components had to exist for the relationship to work:
a) Solid plan towards being in the same place with a (fairly) solid timeline in the near future, ideally within a year
b) Solid plans whereby both parties can continue living their lives without undo hardship once together (thinking career paths here)
c) Work on the part of both parties to make the timeline and plan happen, either through more work and savings, taking a second job, etc.
d) Open communication about expectations for travel and visits, money and pay for those visits, realistic discussions about personal limitations (ie "I won't do X just for a visa), knowledge and expectations about the visa or moving process, and a shared willingness and openness about expected sacrifice on the part of one party to "take the hit for the team" and how that may fit in with their life or their life together
I also came to realize that all the pieces won't necessarily be in place when you want them to be, and there can be a far greater likelihood of opportunity later in life.
I was the queen of the LDR (I think I only had a handful of local US bfs, but they were all so dull!) and looking back at some of those "relationships" it is pretty clear that a number of them went on for far too long because there was no clear path or resources to make a move, or a move would have caused undue hardship for one party that they were not willing to make. LDR breakups are, unfortunately, really tough because the distance can skew perceptions and you don't have the benefit of body language. A lot of folks don't understand what you are going through either because they would never contemplate doing it themselves, but it can be very hard to let go. What you are feeling is completely normal!
Looking at your situation as described - if you were to be able to move to the UK in 6 months, what would that mean for you? Would his salary and career expectations over time be enough for you, enough to grow a life together? What if you made more money than him - would that be a problem? What about creating a social life together? Or would there just be more arguments over money and distance created?
I am also on a forum for expats moving to Sweden and Sweden has a ridiculously easy residency visa classification for LDR partners to move over. A lot of people take this option and invariably just as many move back within 2 years because they didn't realize the impact on their career, couldn't be dependent on another person, their partner didn't want the burden of supporting someone who couldn't find a job/had difficulty learning the language/faced some discrimination issues/depressed due to lack of social contacts, etc. What was exotic initially soon became commonplace and if the couples weren't already on the same page about path and sacrifice, etc well it was a breakup waiting to happen.
There was a lot of great advice posted above, and I think you are aware of what needs to happen. You may want to put a timelimit on this all - maybe 6 months to see what happens by then, if you get to visit, how that goes, if he is able to expand his income, etc and how you feel about the situation then. If it hasn't improved, then perhaps it is time to move on.
Finally - don't feel guilty about going out with friends! You are young once; enjoy it and make the most of it! Live your life for where you are here and today.