Fair play to you for keeping at it through the winter, especially since switching from the bike to a run can make your legs feel absolutely like lead at first. If you haven't already, try doing a few "brick" sessions where you go straight from a quick bike ride into a short run, as getting used to that weird jelly-leg feeling is half the battle. Sounds like you're tracking for a brilliant time in May, so just keep doing what you're doing and enjoy the trial run in April!