Triathlon training nerves

With my triathlon training due to start in two weeks I am already nervous about my fitness levels. I have been away the last two weeks and done no training apart from lifting burgers and pints. I went to the gym this morning to get some motivation back. I did bench press, squats, bent over row, upright row tricep extensions bicep curls cable rotations and hanging leg raise. All 3 sets of 12 reps followed by 15min bike trying to keep cadence around 90rpm then 5 min run. I feel ok my back is a bit tight. I think I am going to do Some heavy bike and run interval sessions over the next two weeks to try and bring my fitness up.