I gained 5lbs in one week

I'm freaking out. I'm 17 weeks pregnant and at 16 weeks I weighed 139, and today I weigh 145. I gained 10 lbs in my first trimester. I started pregnancy at 129. I'm 5'10 so the dr said I needed to gain a little weight. But this is not a little. I have to eat a full meal every 3 hrs to keep from dry heaving. I'm starving and have no appetite so I've been force feeding myself for 4 months. If I continue at this rate I will actually be obese. Has anyone else experienced this kind of weight gain? I can't stop eating or I'll just dry heave all day. Someone please help.