I think everyone here is on point with the tips and advice.
My comic, Cryptic Yume, has only 13 subscribers. Even though that's not much, I say to myself, "Well, at least I have readers." Haha But yeah, don't feel bad. Over the years, I've learned to do a few things:
1. Promote yourself (advertise your work). Project Wonderful and other places are good sites to advertise. More info about that here: http://forums.tapastic.com/t/free-self-promotion-through-project-wonderful/962
2. Go on Social Media and share your work (Facebook, Twitter, Tapastic, DeviantArt, etc.)
3. Make comic friends. Show your support to other comic creators and like/comment their work. Helping them to improve and giving them constructive criticism helps. Oh, be sure to be friendly!
4. Schedule. It's best to have a schedule for your comic and keep your readers updated. For example, I'm going to have my comic updated on Mondays and Fridays. Try to be flexible with the schedule, to make it easy on yourself. If you have to do one day of updating, that's fine! Just make sure you draw sketches and post them to keep your readers interested.
5. Strive to improve. Once you share your work with others to see how you can improve your comic (such as groups and forums), people are willing to help. Now, you'll get good criticism that'll definitely help. Then you'll get criticism that might hurt you. But don't let it get to you! Stay humble and listen. Yes, it's good to stick up for your work and what you believe in. But just humble and positive.
6. KEEP ON DRAWING, MY FRIEND. This is very important. Drawing and telling a story are your passion. I can actually see that in your comic. As long as you keep drawing, ask for reviews on your comic to improve, and never give up, something good will happen. Keep practicing and drawing.
7. Last, but certainly not least, have confidence in your work and in yourself. Like I said, never give up. Keep on drawing. Heck, if you have 5-10 subscribers, that's something! But as long as you keep telling your story and sharing your work, you'll get more subscribers.
And remember: It's not about getting subscribers and being popular. It's about the passion and not giving up on your gift of art and storytelling. I hope this helps. 