If you're full time, you can't get housing benefit as a student. There are things you can get but most benefits are restricted.
What about going part time from next year? It would take you another 3 or 4 years to complete rather than 2 (either doing 2/3/3 modules to accommodate young baby, 3/3/2 to accommodate dissertation module or 2/2/2/2 to spread the workload out as much as possible) BUT I found it so much more manageable this way, with two modules, I only ever had 2 essays due in at the same time max, which is manageable, as you just start them earlier. They used to advise us to start 2-3 weeks before a deadline in first year, I allowed an extra week to make up for the fact I had limited study time, and then allowed an extra week if I had 2 on the go at once, so starting up to 5 weeks before the deadline. The problem if you had 3 or even 4 essays due in at once, is that you end up having to start them before you've covered the topics, unless you're very quick at writing essays and skilled in covering topics in short bursts of time.
Also, if you're part time certain benefits become open to you which can help financially. However, the drawbacks are not staying with the same student group year on year which can be quite demoralising (but then, it's pretty hard when they're all going out partying and you're stuck in with a baby anyway, and if you did a 3/3/2 or 2/3/3 arrangement you'd be in a mixture of groups with people you'd move up with.)
I found a flexible childminder which was perfect for me - it costs me about £4 an hour. Factor in travel times and extra study times. Also when the baby is small you may be able to take him or her into the back of a lecture etc in a sling, as long as you're prepared to take them out if they start crying. Or if DP is around in the daytime, he might be able to look after the baby while you study. It might be worth looking into whether he can change his job to one which is compatible with your study hours or whether you can change to modules which offer courses in the evening.
Good luck! It's totally doable - don't worry about the money now. Ask for help and support, and everything will sort itself out.