Hi there, csennington.
You can put or assign your full-time job in recruitment as personal income since the employment is not part of your business and taxes were paid during that 3months period by your employer. However, I still suggest consulting an accountant to assist you further in choosing the category with your transactions.
For additional information on categorising entries from an online bank account or entered manually, you can refer to this article: Categorise transactions in QuickBooks Self-Employed.
Please refer to this article to see different details of how Quickbooks Self-Employed is designed to help you track your business income and expenses, and prepare your taxes when due: QuickBooks Self-Employed Overview.
Feel free to post here in our forum if you have additional questions or clarifications. I'll be right here to help you anytime. Have a lovely week!