Need Constipation help, too thin, extremely depressed.

I have had problems with constipation throughout my life. In the recent two months, things have become quite terrible. I am generally in agonizing stomach pain due to constipation and have gone to the ER twice in the past month. Both times I went to the ER, they did a catscan for appendix issues and told me I was constipated, should drink more water and sent me home. I don't have insurance, so this is going to end up costing me just over $14,000! (I drink tons of water and I almost started crying the last time they told me this because I can not afford this amount of money and will be paying it back for years and years.) Another factor is that I am extremely thin and losing weight due to eating less to help combat constipation. I would prefer to not be thin at all, but every time I eat a big meal, it seems to be highly regrettable. I search the internet all day when I am not working for foods to eat/not eat. Every source seems to lead me to another $50 miracle cure that leaves me broke and still constipated. I try not to take laxitives much because of what many sites have claimed about electrolyte imbalances/lazy colon, etc, but do take them every few days it seems. Lately even those have not been working. I eat a high fiber cereal in the morning, eat fruit throughout the day and have cut out meat, some wheat, and most dairy from my diet. This ordeal leaves me frustrated and immensely depressed. I don't know how much longer I can live like this. Anyone who has constipation problems knows that it takes a toll on every moment of everyday and activity in life. I feel as though I'm just carrying my body through the motions of living hoping that something will break and I will feel normal again. To top it all off, I have grade IV hemorrhoids due to the constipation throughout my life. This creates a vicious cycle because it seems that one is making the other worse or vice versa. If anyone has some advice I would love to hear it. I'm getting desperate. I've tried bulking up on fiber/water intake/I consume some biolife pill with supposed probiotic abilities. Regarding losing weight, are there any foods I can eat a lot of that will aid in helping my constipation/not constipate me, so I can take in more calories in a day. I no longer enjoy eating, so any suggestions are welcome even if not enjoyable. Thanks.