Since Returning From A Trip To Cuba And Experiencing An

Since returning from a trip to Cuba and experiencing an allergic reaction to over 150 mosquito bites I have been feeling unwell, headaches, sore throat and feel generally flat and unable to carry out daily duties. I feel exhausted most of the time and unrested when I awake each morning. I have had the majority of blood tests taken, including ECG tracing and chest Xray, which were all normal, what could be my problem?