At about 90 subscribers, one or two comments seems like you're doing quite well! Especially given how enthusiastic those comments are. I have a little over 100 subscribers here on Tapastic, and "one or two comments on some pages" is about what I get! Tumblr is worst of all as far as feedback goes -- it's where I got the fewest responses for a long time.
@Chiper1811 speaks truth -- the percentage of people who comment and engage is always going to be a very small percentage of your total readership.
I don't fully understand your comic's goings-on in the past few months, but it looks like you took a break, reworked the beginning, and posted a different comic in the meantime? Honestly, that is when your readership is going to be at its LEAST enthusiastic, so if you're noticing a decline in response or interest, it probably has more to do with the redraw-hiatus than anything! I've personally found the decline in feedback during my hiatus really discouraging, so I understand why it feels that way, but you gotta remember there's a reason it's happening!
When I was first starting out, a more experienced webcartoonist told me "You have to just focus on your comic for at least 2 years before you can decide if it's for you or not." And while I think it's tough to put a hard number on webcomicking -- it might be a little more than 2 years, it might be a little less -- that advice still rang true for me. You have to go into it knowing that for a couple of years you're not waiting to see if it's catching on -- you're just updating. If you discover that process is REALLY not enjoyable before then, then I think it's fine to go "this ain't for me," but if you're discouraged that you're getting no response and you're still in that first two years of updating..... please understand, that's normal!!
I agree with everyone saying "Do it for yourself," but at the same time, I can understand really needing someone who cares and gives you feedback on what you're doing. I think I'd have a tough time making a comic and getting zero response. But you've said that your peers/friends do read and respond to your comic, and it sounds like, from looking at some of the comments you get, that you do have 1 or 2 dedicated people who tend to respond often. THAT IS AWESOME! Having a friend who cares about your story during the tough 2-3 years where you haven't really built a responsive readership is a HUGE help, and if you have to think of yourself as primarily making this comic for yourself, and secondarily you know your one friend is gonna love it -- man, I don't think there's anything wrong with that at all.
Webcomics are not for everyone; if you honestly don't want to do it or don't find it fulfilling, that doesn't reflect negatively on your worth as a person or as an artist -- it is okay to decide that's not for you! But if you like creating a webcomic and only feel like you're failing because of where you stand in terms of reader responses, then I will tell you as encouragingly as I can: Nothing could be further from the truth!