When my account limits of payment/SSL submissions are used up for the month, will all my forms be disabled or just ones that use payment and/or SSL?

I see that your account has already reached the limits for the month by receiving 12 payments and 11 SSL submissions where they are allowed only 10 per month. Hence the account is now scheduled to downgrade by tomorrow. If the account is downgraded, all the forms shall be disabled and will not able to receive any submissions. If you want to continue to receive the submissions, it is required to upgrade your account for a paid subscription or you may wait till the first day of the following month so that submission counter shall be reset. 

Hope this information helps!

Why are all forms disabled? I also use a regular (non-https) contact form and it doesn't even get close to the limit of 100 submissions. It should not be disabled.

Please be noted that the forms shall be disabled when either of the limit is exceeded. Since you have received more SSL submissions for the month, the account is now scheduled to downgrade. I see that you are having some test submissions on one of your forms with payments. I'm resetting the SSL and Payment submissions count to 5 and activating your account which will allow you to receive normal submissions. If the SSL/payment submissions are exceeded for the month, please be noted that it is required to upgrade your account.

Please let us know if we can be of any further help. Thanks!