I'm not sure about squats and tummy exercise and would probably want to consult a gynae on these before proceeding. But I feel walking might be a safe, less strenuous option that you can consider for a start! I also didn't have confidence when we were TTC cos of the weight gained during circuit breaker (haha) so I insisted on switching off all the lights when doing it, hahaha! It helped! With regards to your colleagues' and parents' remarks, sigh... If only people can be less unkind. They don't know what others may be going through, and don't realize how their words can hurt/affect others. 😖
Do not be stress about your body. Stress is not good because you are TTC. Eat healthy .. below article may help you for healthy eating https://sg.theasianparent.com/15-most-effective-fertility-boosting-foods-for-women