When I got my staff pick, I had a week of rapidly increasing subs, and then I had a community pick, so the next week my subs were going up too... but then I had this awful month where my subs, while overall they held roughly level, frequently went down. Like I had several days and even a week or two where I ended with fewer subs than I started. It was probably partially due to a bot purge, but I'm certain at least some of the losses were people who quickly bookmarked my comic for later while it was on the front page, then read it and decided it wasn't their thing.
It's never easy. It's definitely worse feelings-wise than somebody just not subbing in the first place. It's a bit like when you're on a table at a convention, somebody picks up your book, looks through it, makes an unimpressed grunt, puts it down and walks away. 
The more subs you'll have, the more you'll lose. People are much more likely to sub and then bail on you if you have more subs, because they'll think it doesn't really affect you (or even they deliberately want you to know they think you're overrated and need taking down a peg), or they were only looking out of curiosity. Sadly Tapas doesn't have different features for "save the link to this series" and "subscribe to update notifications on this series" so people often sub if they just want to look at something later, then when they get round to it, it's actually not their cup of tea. I try to leave off subbing until I'm up to date on a series if possible to avoid this, but it's hard not to then lose the series.
Try to think of it this way: If you lose subs, it means that your marketing is effective. Your work is getting seen and some combo of your cover, blurb or art is catching somebody's eye and making them want to give it a shot. When a bunch of people are checking you out, inevitably a few are going to decide it's not their jam. That feels painful, but it's normal; just think of all the things that you love that you hear other people say "ugh, that sucks, I hate that book/show/comic/game" about! The important thing is, it was seen and somebody gave it a shot.
If the unsubbing is excessive, it may be that your cover or blurb is really catchy but misleading, so people come for something and you're not delivering, OR it could mean your pacing gets bad later and the comic or novel gets boring after a strong start, but the odd one or two unsubs now and again is normal and nothing to worry about.
