Don't text him back .You should let him text you. Don't run after anyone if he still likes you he will text you. If he does not well then you know where you stand with him.
It depends whether he is just booty-calling you or if there is actually a problem. These 'problems' don't include, 'My girlfriend just dumped me and I realised that you're the only one for me.' This,...
give her time and if ur in a relationship with her, txt her and say that u don't want to bother her and that u wanted to tell her u loved her :) if not, give it time <3