NHS psychotherapy is so financially constrained that it's not fit for purpose. It's really saddening, but the only option in this country for most people requiring longer term therapy is to pay for a private therapist. Is this an option for you? If not, it might be worth looking at what charities can offer. Depending on your issues, there are various charities which could offer low cost or free counselling. Here's a list with a few possibilities:
UK-Wide Charities and Organisations | Sirius Project
Also it might be worth checking out what options there are locally.
I'm sorry you're going through this kind of situation. Mental health provision on the NHS is sadly woefully inadequate.