I was in this exact situation about 2 years ago. I'm 31 and have been with DH for 5 and a half years now. I met my DH while working as a Network Engineer in the same IT department. I really started lamenting that I missed having a female best friend, as I hadn't had one since my sophmore year of high school. I stayed in touch off and on with the two girls I considered my best friends, but life happens, we all know that.
My friend circle really dwindled after I made the decision to take a sabbatical from work due to burnout from office politics, and I didn't retain any friends from the job except for the DH who was still a relatively new boyfriend (1.5 years). So I literally had two friends, both male engineers that are so hard wired to look at everything with a logical mind they both border on emotional retardation at times :P Sometimes, I really just wanted someone to listen to me instead of attempting to fix the problem!
I'll be honest, I've got awkward down well, and I have the same issue other PPs have discussed...I say really weird inappropriate shit to people I barely know and then I beat myself up about it for the next year (or 5). On top of that, I'm REALLY passionate about my hobbies, the normal things a 30 year old woman is interested in...video games, nerdy fandoms, and purposely breaking my electronics so I can figure out how they work! 
I had resigned myself to the fact that the chance of me finding a REAL female friend was probably not going to happen. Bummer, but not willing to change who I am or pretend to like things I consider to be a terrible bore just for female companionship.Well one Sat evening my boyfriends doorbell rang and I huffed a bit as his friends never call before stopping by which drives me bonkers. So he opens the door and I hear a male voice and then a female voice behind it. They're friends of his that he's known for 15+ years, so while still not impressed to be receiving visitors unannounced at 11pm...I say hi, offer a couple drinks, then promptly bury my head in my tablet as my anxiety around new people is often overwhelming. The girl was sitting on my couch while I'm thinking "Who's this great female friend I've never heard of? Hmph!" And then nerdy fate intervened when she asked my DH if he had played a particular video game, and he hadn't but he said "No, but you know that ExceptionFatale is into gaming, I think she has." I think we ended up talking for 3 hours straight that night, and when she left she got my number and texted me the very next day to hang out.
It's been almost 2 years since then and she is my absolute best friend in the world and I honestly adore the woman. I was so neurotic and worried I'd fuck up our friendship by being my weird neurotic self. I apologized to her for not knowing how to "friend" properly and she just gave me a hug and told me that everything was fine, she was just as happy to have a real female friend again. The cool thing is that while we still have our nerd hobbies, she's shown me that I actually do like doing "girly things" like going shopping and having spa days. Things that were outside of my comfort zone before, and I honestly feel far more well rounded as a person than I was.
Sorry for the tangent, my point is that water really does seek its own level which can be great in some cases. Someone worthy of being your friend won't judge you for not "dressing smart" or foregoing makeup or for putting your foot in your mouth occassionally. Any friend I would have made adhering to someone elses expectations of how I "should" look like or be dressed/made-up/coiffed would be a shallow bitch I'd want nothing to do with.
The only other advice besides not putting on some fake version of yourself is to seek out friends based on your interests and hobbies, I think it's an enormous amount of pressure to put on yourself that something is wrong with YOU because you didn't get along with a group of women you literally knew nothing about other than you both shared a life occurance that's fairly common to the rest of humanity. So whatever it is that you love doing, or are passionate about, get involved with it and talk to the other women that are involved too 
BTW...about the mommy groups...I can't bite my tongue about this so can I just say that I think a lot of these women are so cliquish and competitive; I've found personally that this bitch behavior stems from the fact that they litetally have no identity beyond "mommy", so when someone that has a developed sense of self, their own dreams and interests they will freeze that woman out of the group or go full on catty mode. People like people who are interesting, I think it can be very threatening to some of these women. Just my 2c!