It sounds to me like you've diagnosed your immediate issue, but there is definitely more going on underneath that you need to work on.
While not a perfect law of the universe, you generally get out of something what you put into it. If you are putting zero effort into cultivating relationships with people than it is expected you won't have them, romantic or otherwise. This is an important causal concept to understand, and you should manage your expectations accordingly.
There is nothing wrong with de-prioritizing social relationships if it suits you, but it doesn't sound like that is what you want. Your loneliness stems from more general social isolation than simply not having a girlfriend. You have to ask yourself some difficult questions about what you really want in life, you are just floating through it on autopilot. That path leads nowhere, and certainly not to fulfillment.
You also need to reflect on your feelings, actions, and how those affect your relationships. Feeling like a third wheel among friends and texting your mother those words indicates you aren't of right resolve (not to get too Buddhist). Why did you say those things? What purpose did it serve? If your mother is someone not worth having in your life, then don't have her in your life. Why do you feel like a third wheel among good friends? Is it all in your head, or are they not people worth being friends with? Stop blowing time and mental energy on people and relationships that don't bring meaning to your life.
Not being able to find a girlfriend is only a symptom and in your current state, even if you managed to find one, I fear you would choose poorly. You really should start counseling again, even if it didn't do much before it is worth pursuing. If you need to shop around until you find someone you connect with.
