I'm rather thin as well, and like you I was seeking ways to put on some weight. I began eating like crazy, about 3k calories a day and exercised and added 10 pounds in 3 weeks. You can stick with what you eat now, just find creative ways to increase your calorie count without eating 10 meals a day. I found nuts and seeds to be my best friends. Here's what I do: Put a banana and walnuts in my oatmeal (each fourth cup of walnuts has 200 calories, and a banana has about 75 calories), add sunflower seeds to my PB&J sandwiches (around 200 calories per oz). Add pepitas to certain meals (rice, pasta, etc). Add extras whenever possible. Add avocado to your wraps/sandwiches. If you like cereal, granola is high in calories. Get some snack bars to eat between meals. Add fruit. If you eat and eat and eat, you will gain weight, but fat not muscle (muscle weighs more than fat). To turn the extra calories to muscle you need to work out and take a protein shake after it (has to be whey, not soy or any other if you want faster results). Here are some basic points:
1. Always add nuts and fruit to your oatmeal
2. Always add fruit to your cereal
3. PB&J sandwiches with sunflower seeds = massive calories, about 500.
4. Eat lots of extras when you're not having a meal, such as snack bars or fruit
5. Eat large portions of pasta and rice if you like it, it's high in calories
6. Buy yourself some free weights, maybe 10-12 pounds. Do arm curls, shoulder presses, chest presses, etc. with them. Also add push ups and sit ups. These are the types of exercises I do. Try to work out at least 3 days a week (more if you can), for at least 30 mins each day, and push yourself with your exercises so you do as many reps as possible, but not to the point where you feel weak and like passing out. Start off slow, and build it up as you become stronger.
7. Take whey protein after your workout (i know it's not vegan, but soy or any other protein isn't gonna give you good results).