I haven't been eating well lately and haven't been to the gym in a while. could this be the cause to my constipation? any tips on how to fix it?

Heal yourself: You probably have answered your own question. I recommend a good diet with fruits, vegetables, and whole grains. Drink plenty of water and other fluids. Add daily metamucil powder as directed. Add yogurt to your diet 3-4x per week. Certainly you need some form of regular exercise, preferably with some aerobic activity at least 3-4x per week. Avoid chemical laxatives. Good luck.