Hey there, goodness, me too. Went through a stage in last couple of weeks of waking at 4.30, then 4, then 3.30, and not being able to get back to sleep, because as soon as I felt myself dropping off I'd get this sort of panic-adrenaline kick, which would wake me up. Also, I'm a single mother too - and am currently living at my sister's, and sharing a room with my 14-month-old - and doing a pretty demanding, stressful job four days a week - so when I woke up, I'd think 'bugger, must get back to sleep, or tomorrow will be a disaster' - and then, of course, I couldn't.
So ... I went to see the doc about it last week. 'Sleep tends to be connected to the rest of your life,' he said. 'Are you depressed at all? Tearful?' - at which, naturally, I burst into tears! Thing is, I don't feel depressed on a day-to-day level, but I guess I am pretty stressed out, and this was how it manifested itself. He prescribed counselling (which I'll begin next week) and 14 sleeping pills, to break the cycle of bad sleep. They're just diazepam, so don't send you into a deep sleep, but are basically anti-anxiety. For the last few nights, I've taken half a pill before going to sleep, and even when I've woken up, because I knew I could take another half-pill if necessary, I've just dropped straight back off! Planning on not taking any tonight to see how I go.
So ... in short, definitely worth seeing your doc, I reckon. It is deeply stressful, not being able to rely on your sleep!