I'd say think very very carefully about doing this.
If you're only a year post-qualified then you are potentially limiting your longer-term career as only doing bank and agency work could really limit your future job prospects. You may be considered as inexperienced, poorly skilled or not a team player, which can hamper applications.
Agency can be a money spinner, especially if you are in a specialist area or have additional qualifications, but IME you tend to be thrown in as just another pair of hands and may not develop the skills and experience you need.
I know where I work (and where my DP manages) you'd not be called for interview if you applied to work for us having only 1 years PQ experience on a general ward, and then only agency experience.
There is a massive drive in many trusts to not use agency nurses and to rely on bank staff if needed, and even then sparsely.
If you are experiencing stress and anxiety currently, then agency may exacerbate that - it can be soul destroying being just a pair of unappreciated hands, with no consistency, no professional development, no pastoral support from your team or line manager.
Of course for some, agency/bank is perfect for them but I'd hazard a guess that they are older, have some years of nursing behind them and are not overly reliant on having to earn xx amount per month.
(Oh and just out of curiousity - how do you have student loan fees to pay off? Did you do another course prior to your nursing training?)