I'm sure you didn't wait too long. I think they said you have to reply within 7 days, so you should be just fine.That's awesome!
We applied for inland spousal sponsorship too, but we submitted it on March 31st.
We also received the first Portal email on July 12th, replying one day after, on July 13th.
We're still waiting for that second email to sign in. I hope we don't wait too long just because we replied to that first email one day after.
I should specify that we already had a PR Portal account which I set up months ago, because I misunderstood the application process initially and thought that was how we would apply. So maybe ours came quicker because we already had an account? I do not know.
At any rate, I really hope you get your sign-in email soon !