Being in love is probably the most powerful feeling I've ever experienced. It is the absolute best and sometimes also worst feeling in the world. The tremendous sense of connection and joy of being with someone also carries with it the most vulnerability you can ever feel, plus the stress and worry that comes with not being around your loved one at times.
If you're curious about whether or not you are truly in love with someone that you developed feelings for, then EliteDaily has a 21-point checklist you can go through to try and sort it out. If you're just more generally curious about what it's like to be in a state of love, then LiveScience has a list of 13 actual physical results and phenomena related to the emotion.
Other than that, when it comes to describing love, there's a thousand poets that can sum it better than I can.