Lots of really good advice here....don't have time to read it all but I spent the first 15 - 16 weeks of ds life (he's now 22 weeks) working at the naps and I'd say 90% of the time now, he naps really well. I was so relieved every time I got the end of the day and finally had my evening to myself after what seemed like a life's work trying to get him to sleep every which way. My dh works 7am to 8pm ish and I felt (and still do often) like a single mum, so sympathies to you.
From my own experience:-
Try using your buggy as much as possible to get them used to sleeping at a certain time. At lunchtime, my ds would sleep for 45 mins and then be wide awake. I took to putting him in the buggy indoors, curling up on the sofa with a good book and when I could hear him stir after 45 mins, rock the buggy and get him off again. I used a dummy for a while (he now sucks his thumb). Now, he may go the full 2 hours or so, sometimes less, but I feel a lot less stressed about it. If I am out, I always take him in his car seat so if I am in a coffee shop or something can rock him off to sleep if he stirs and get a bit of peace and quiet.
Are you happy about going out for a walk late afternoon ?- I know it's dark early now, but I always feel so much better after getting a bit of fresh air before bedtime and ds will nearly always drop off for a half hour or so. I might use this time to pop to the shops for a few bits.
From the "social" side, I go stir crazy stuck in the house every day, so have a set day to meet ante natal friends, a couple of set mornings to do a class at the gym (ds in the creche, he loves it) which in themselves make me feel so much better. I do have family nearby so can get some time off but do you have any one who would take dd for an hour or so??
Let your dh do things even if not quite to your liking. I'm a complete control freak and find it very hard to surrender responsibility, so rather than "supervise", I have to leave the room and do something else and let him get on with it. One lady I met recently with 5 children said that the best piece of advice someone gave her was to "allow" her dh to do the jobs for the kids even if she could do them twice as quick. She said she often comes home to find the place in a tip (not surprising with 5 kids) but the kids are happy and fed but it means she can get away sometimes and know he can cope in his own way. My dh hates being "told" what to do, but after a while, he found his own way and it we seem to achieve the same result. I don't expect him to get up in the night as he goes to work the next day, but I do ask him to do other things if he is seeing what he can get away with (!!)
I think motherhood can be extremely boring sometimes - I often find myself wandering round Tesco at about 3pm, just wanting to get out - buying a couple of items and it taking me about an hour. Even meeting up with the same people week in and out can feel like a drudge, but at least we're all in it together,
Oh, and Mumsnet is a lifesaver - I'm an addict.
Good luck and keep posting.