well you have us although I know we can be a right bunch of old miseries at times , at least I can.
I think you'll be able to maintain your friendships in the UK if you put in an effort with emails and going to see people when you're back in the UK on holiday. It isn't that far and there are cheap flights so it should be possible for you to do that. Is this your first experience of living overseas?
You'll find there are a lot of English speaking foreigners living in Germany, especially in big towns, so there is bound to be a newwork there, you just need to discover it.
Think I'd consider finding a nice babysitter, maybe a student of English from the university, early on so you and dh can go out at night at least once a week and have a bit of fun. You don't want to be cooped up all day being a housewife with no adult to speak to IYSWIM. That's a fine recipe for feeling depressed and lonely.
I've found Germans on the whole like meeting people they can practice their English with, so you needn't be lonely. Germans (unlike us I think) invite people into their homes readily and are quite open to making new friends. The culture is different enough to be interesting but not so different that you'll be at sea here.
There are things that are great about living here, because as you'll see, Germans just do organise things a lot better. In some ways they seem light years ahead. There are other sides to life which may grate on you (like everywhere really) but I think you have to just be resolved to take those with good humour, if you can. As admylin said you know it isn't forever and so I think it is easier to shrug off things that annoy you and have a good natured laugh about them when you know you won't be dealing with them forever.
Think if you and dh resolve to drive about at the weekends a lot, seeing the place, eating out, going to beer gardens and things, it should be a nice experience for you. Everyone panics a bit at the thought of moving overseas but you need to get into excited mode now and look forward to it as a bit of an adventure, don't you think?