If you've bought a bus pass does that mean you've got some money to spend does DP like to know what you are spending too? Are you able to talk to him about sharing the care of your Lo?
Can totally sympathise with feeling lonely. I was in the same position as you, all friends were in work and I felt utterly alone. Is there a children's centre near to you? They usually have some activities you can go alone to and while I'm not guaranteeing you'll make friends, you'll probably meet some local mums who are going through the same things ad you are. If you are bfing, are there any bfing support groups you could go to?
Other places that might have things to go to are your local library, they have story time or music groups. Lo might be a bit young but at least its a chance for you to get out. Your swimming pool might do aquatots, they usually have all the gear your baby will need apart from the swim nappy
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If you are missing your friends are you able to meet up with them in the evening or in the day at the weekend? Wake you be able to get them to come to yours for an evening or would that be out of the question?
See if your library has What Mothers Do. I've not read it but have seen lots of posts from mums just like you who said it really helped.
Have a look at Mumsnet local too. You can ask what local groups are good and there is even a friendship bench.
Keep posting and let us know how you get on.