imo, the way you feel is normal! On the forums we talk a lot about "DONT WORRY ABOUT SUBS" but it's easy to say and hard to do -- if I'm 100% honest, I have to remind myself constantly not to worry and really combat that in myself. It's natural, when you have people looking at you, to be worried about letting them down.
But the thing is, it's really hard to tell how you're doing just by looking at the fluctuating size/interaction of an audience, especially when your comic is so young (only 2 months old!) and you have a staff pick in there throwing things off. There's no way to identify what's normal and what's a good trend and what's a bad trend and what's a random fluctuation in that time frame, imo -- that'd be like flipping a coin three times, getting tails each time, and thinking that there must be something wrong with this coin.
Plus, you can never gauge why people are leaving -- how many expected a different kind of story? How many expected a different character to show up more? How many bookmarked it and then changed their minds a couple months later without even reading the newer pages? You can't judge how you're doing based on unsubs -- and I don't mean that in a "don't do it," sense, I mean that it's literally impossible to glean any useful information from that!
So when you ask "Should I be worried about what it says about quality?" .....I don't think so, not right now. I would say to do your best to not worry about it until you've been updating at least a year. At that point you'll have enough space to be able to gauge whether it was a weird fluctuation or a trend.
I think, to an extent, your gauge of how you're doing kinda needs to come from you, and people you trust. If you look at your comic and it's what you wanted it to be, then don't worry too much -- just keep making it!! If you look at your comic and you're feeling really unsure about something, and it feels like it's not quite right, that's a thing you can bring to people you trust or people in these forums and say "hey, I'm not feeling good about the [pacing/dialogue/colouring/whatever] of my comic, do you guys see anything I could be doing better?" That sense of whether it feels right to you and the advice of people you trust will give you wayyyyy more to work with in making your comic the best it can be than trying to divine the migration patterns of subscribers ever will. ;u;