I've just ended my first relationship of 3 and a half months. I'm not sure why I freaked out with a few things, and instead of communicating I opted for the easy option. I'm not sure how I feel now my emotions are up the wall and I have very mixed feelings. When we have no contact I'm sad, think about him, want him, miss him like crazy and get very upset. But when I have little contact with him even so much as a text I feel all happy and feel like I can focus a bit more. What does this mean? Do I miss him? Is my heart with him? Or is attention? And initial lack of feeling wanted?

Give yourself time to figure it out, and let your emotions settle down. The last thing you need is to make another impulsive decision. What was the fuss about, and how old are you?

What you're feeling is normal. When he contacts you, even just a little bit, that means he at the very least cares about you just enough to still talk to you. This is conforting, but it isn't a sign that things will change and shouldn't be looked at this way.

You sound young, so it's time for a rebound! DATING! Go out and get your groove on with a new guy, but don't go too far and not too fast. Dinner, make outs, talking, etc. Small things. You'll be over it before you know it!

Your story is a bit vague.

I feel sad and lonely when my guy doesn't call/text me enough. Best remedy I found are sports and doing busy things like going out with friends and joining a club.

Just because you two started getting dating/exclusive doesn't mean he's going to drop everything so he can call you or text you or think of you all the time. You two have separate lives before you started going out so accept that and you will feel better when you get into another relationship. Keep your own life going.