I need help finding solutions for "very" small business recurring invoicing. I currently have 5 clients and need to invoice monthly. I would

It may be too early for you to look at an automated solution. Traditionally most small companies start with shrink-wrapped accounting (like QuickBooks) combined with spreadsheets for additional required schedules. At some point companies outgrow this model, transitioning to more advanced business systems as well as industry specific product functionality like managing customer contracts.
There are benefits to systems – greater visibility into your information, greater consistency in your approach to business needs, better audit compliance, scalability for your organization, and productivity when manual systems become unwieldy. There are some business changes that go along with these benefits you need to understand and embrace as part of this change. These changes include more structure to your business transactions and your business process as well as a focus on consistency and repeatability.
One reason it may be too early to consider a software solution with five customer recurring invoices is the greater structure required with such a system. With five customers you can review and update your spreadsheet easily. At one hundred customers even simple renewals become complex to manage well.
Reasons to look at a system now would include potential for rapidly scaling your organization, significant complexity in your monthly renewals (usage based combined with subscriptions or milestones), or outside investors in your company who want the assurance that comes with a systematic approach to managing your billing processes.